2cos (problem 3.3.5)

Percentage Accurate: 37.2% → 99.3%
Time: 17.5s
Alternatives: 16
Speedup: 1.9×

Specification

?
\[\begin{array}{l} \\ \cos \left(x + \varepsilon\right) - \cos x \end{array} \]
(FPCore (x eps) :precision binary64 (- (cos (+ x eps)) (cos x)))
double code(double x, double eps) {
	return cos((x + eps)) - cos(x);
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = cos((x + eps)) - cos(x)
end function
public static double code(double x, double eps) {
	return Math.cos((x + eps)) - Math.cos(x);
}
def code(x, eps):
	return math.cos((x + eps)) - math.cos(x)
function code(x, eps)
	return Float64(cos(Float64(x + eps)) - cos(x))
end
function tmp = code(x, eps)
	tmp = cos((x + eps)) - cos(x);
end
code[x_, eps_] := N[(N[Cos[N[(x + eps), $MachinePrecision]], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\cos \left(x + \varepsilon\right) - \cos x
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 16 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 37.2% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \cos \left(x + \varepsilon\right) - \cos x \end{array} \]
(FPCore (x eps) :precision binary64 (- (cos (+ x eps)) (cos x)))
double code(double x, double eps) {
	return cos((x + eps)) - cos(x);
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = cos((x + eps)) - cos(x)
end function
public static double code(double x, double eps) {
	return Math.cos((x + eps)) - Math.cos(x);
}
def code(x, eps):
	return math.cos((x + eps)) - math.cos(x)
function code(x, eps)
	return Float64(cos(Float64(x + eps)) - cos(x))
end
function tmp = code(x, eps)
	tmp = cos((x + eps)) - cos(x);
end
code[x_, eps_] := N[(N[Cos[N[(x + eps), $MachinePrecision]], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\cos \left(x + \varepsilon\right) - \cos x
\end{array}

Alternative 1: 99.3% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.004:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \sin \varepsilon \cdot \left(-\sin x\right)\right) - \cos x\\ \mathbf{elif}\;\varepsilon \leq 0.004:\\ \;\;\;\;\left(\sin x \cdot \left(-0.125 \cdot \left(\varepsilon \cdot \varepsilon\right) + 1\right) + \cos x \cdot \left(\varepsilon \cdot 0.5 + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -0.004)
   (- (fma (cos x) (cos eps) (* (sin eps) (- (sin x)))) (cos x))
   (if (<= eps 0.004)
     (*
      (+
       (* (sin x) (+ (* -0.125 (* eps eps)) 1.0))
       (* (cos x) (+ (* eps 0.5) (* -0.020833333333333332 (pow eps 3.0)))))
      (* -2.0 (sin (* eps 0.5))))
     (- (- (* (cos x) (cos eps)) (cos x)) (* (sin eps) (sin x))))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -0.004) {
		tmp = fma(cos(x), cos(eps), (sin(eps) * -sin(x))) - cos(x);
	} else if (eps <= 0.004) {
		tmp = ((sin(x) * ((-0.125 * (eps * eps)) + 1.0)) + (cos(x) * ((eps * 0.5) + (-0.020833333333333332 * pow(eps, 3.0))))) * (-2.0 * sin((eps * 0.5)));
	} else {
		tmp = ((cos(x) * cos(eps)) - cos(x)) - (sin(eps) * sin(x));
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if (eps <= -0.004)
		tmp = Float64(fma(cos(x), cos(eps), Float64(sin(eps) * Float64(-sin(x)))) - cos(x));
	elseif (eps <= 0.004)
		tmp = Float64(Float64(Float64(sin(x) * Float64(Float64(-0.125 * Float64(eps * eps)) + 1.0)) + Float64(cos(x) * Float64(Float64(eps * 0.5) + Float64(-0.020833333333333332 * (eps ^ 3.0))))) * Float64(-2.0 * sin(Float64(eps * 0.5))));
	else
		tmp = Float64(Float64(Float64(cos(x) * cos(eps)) - cos(x)) - Float64(sin(eps) * sin(x)));
	end
	return tmp
end
code[x_, eps_] := If[LessEqual[eps, -0.004], N[(N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision] + N[(N[Sin[eps], $MachinePrecision] * (-N[Sin[x], $MachinePrecision])), $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 0.004], N[(N[(N[(N[Sin[x], $MachinePrecision] * N[(N[(-0.125 * N[(eps * eps), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision] + N[(N[Cos[x], $MachinePrecision] * N[(N[(eps * 0.5), $MachinePrecision] + N[(-0.020833333333333332 * N[Power[eps, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(-2.0 * N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision] - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.004:\\
\;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \sin \varepsilon \cdot \left(-\sin x\right)\right) - \cos x\\

\mathbf{elif}\;\varepsilon \leq 0.004:\\
\;\;\;\;\left(\sin x \cdot \left(-0.125 \cdot \left(\varepsilon \cdot \varepsilon\right) + 1\right) + \cos x \cdot \left(\varepsilon \cdot 0.5 + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -0.0040000000000000001

    1. Initial program 46.5%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. cos-sum98.5%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \]
      2. cancel-sign-sub-inv98.5%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon + \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
      3. fma-def98.6%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]
    3. Applied egg-rr98.6%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, \left(-\sin x\right) \cdot \sin \varepsilon\right)} - \cos x \]

    if -0.0040000000000000001 < eps < 0.0040000000000000001

    1. Initial program 21.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos41.4%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv41.4%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. associate--l+41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\color{blue}{\left(x + \left(\varepsilon - x\right)\right)} \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. metadata-eval41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      5. div-inv41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      6. +-commutative41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} + x\right) \cdot \frac{1}{2}\right)\right) \]
      7. associate-+l+41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(\varepsilon + \left(x + x\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      8. metadata-eval41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr41.4%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. associate-*r*41.4%

        \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)} \]
      2. *-commutative41.4%

        \[\leadsto \color{blue}{\sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right)} \]
      3. *-commutative41.4%

        \[\leadsto \sin \color{blue}{\left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      4. +-commutative41.4%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      5. count-241.4%

        \[\leadsto \sin \left(0.5 \cdot \left(\color{blue}{2 \cdot x} + \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      6. fma-def41.4%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\mathsf{fma}\left(2, x, \varepsilon\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      7. sub-neg41.4%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \color{blue}{\left(\varepsilon + \left(-x\right)\right)}\right) \cdot 0.5\right)\right) \]
      8. mul-1-neg41.4%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon + \color{blue}{-1 \cdot x}\right)\right) \cdot 0.5\right)\right) \]
      9. +-commutative41.4%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \color{blue}{\left(-1 \cdot x + \varepsilon\right)}\right) \cdot 0.5\right)\right) \]
      10. associate-+r+99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(\left(x + -1 \cdot x\right) + \varepsilon\right)} \cdot 0.5\right)\right) \]
      11. mul-1-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\left(x + \color{blue}{\left(-x\right)}\right) + \varepsilon\right) \cdot 0.5\right)\right) \]
      12. sub-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\color{blue}{\left(x - x\right)} + \varepsilon\right) \cdot 0.5\right)\right) \]
      13. +-inverses99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\color{blue}{0} + \varepsilon\right) \cdot 0.5\right)\right) \]
      14. remove-double-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(0 + \color{blue}{\left(-\left(-\varepsilon\right)\right)}\right) \cdot 0.5\right)\right) \]
      15. mul-1-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(0 + \left(-\color{blue}{-1 \cdot \varepsilon}\right)\right) \cdot 0.5\right)\right) \]
      16. sub-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(0 - -1 \cdot \varepsilon\right)} \cdot 0.5\right)\right) \]
      17. neg-sub099.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(--1 \cdot \varepsilon\right)} \cdot 0.5\right)\right) \]
      18. mul-1-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(-\color{blue}{\left(-\varepsilon\right)}\right) \cdot 0.5\right)\right) \]
      19. remove-double-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\varepsilon} \cdot 0.5\right)\right) \]
    5. Simplified99.0%

      \[\leadsto \color{blue}{\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)} \]
    6. Taylor expanded in eps around 0 99.8%

      \[\leadsto \color{blue}{\left(\sin x + \left(-0.125 \cdot \left({\varepsilon}^{2} \cdot \sin x\right) + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    7. Step-by-step derivation
      1. associate-+r+99.8%

        \[\leadsto \color{blue}{\left(\left(\sin x + -0.125 \cdot \left({\varepsilon}^{2} \cdot \sin x\right)\right) + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      2. associate-*r*99.8%

        \[\leadsto \left(\left(\sin x + \color{blue}{\left(-0.125 \cdot {\varepsilon}^{2}\right) \cdot \sin x}\right) + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      3. distribute-rgt1-in99.8%

        \[\leadsto \left(\color{blue}{\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x} + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      4. +-commutative99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \color{blue}{\left(0.5 \cdot \left(\varepsilon \cdot \cos x\right) + -0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right)\right)}\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      5. associate-*r*99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \left(\color{blue}{\left(0.5 \cdot \varepsilon\right) \cdot \cos x} + -0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right)\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      6. associate-*r*99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \left(\left(0.5 \cdot \varepsilon\right) \cdot \cos x + \color{blue}{\left(-0.020833333333333332 \cdot {\varepsilon}^{3}\right) \cdot \cos x}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      7. distribute-rgt-out99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \color{blue}{\cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)}\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    8. Simplified99.8%

      \[\leadsto \color{blue}{\left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right)} \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    9. Step-by-step derivation
      1. unpow299.8%

        \[\leadsto \left(\left(-0.125 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    10. Applied egg-rr99.8%

      \[\leadsto \left(\left(-0.125 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]

    if 0.0040000000000000001 < eps

    1. Initial program 56.2%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg56.2%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum98.9%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} + \left(-\cos x\right) \]
      3. associate-+l-98.8%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      4. fma-neg98.9%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    3. Applied egg-rr98.9%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    4. Step-by-step derivation
      1. fma-neg98.8%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      2. *-commutative98.8%

        \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x} - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right) \]
      3. *-commutative98.8%

        \[\leadsto \cos \varepsilon \cdot \cos x - \left(\color{blue}{\sin \varepsilon \cdot \sin x} - \left(-\cos x\right)\right) \]
      4. fma-neg98.9%

        \[\leadsto \cos \varepsilon \cdot \cos x - \color{blue}{\mathsf{fma}\left(\sin \varepsilon, \sin x, -\left(-\cos x\right)\right)} \]
      5. remove-double-neg98.9%

        \[\leadsto \cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \color{blue}{\cos x}\right) \]
    5. Simplified98.9%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)} \]
    6. Taylor expanded in eps around inf 98.8%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \left(\cos x + \sin \varepsilon \cdot \sin x\right)} \]
    7. Step-by-step derivation
      1. associate--r+99.1%

        \[\leadsto \color{blue}{\left(\cos \varepsilon \cdot \cos x - \cos x\right) - \sin \varepsilon \cdot \sin x} \]
      2. *-lft-identity99.1%

        \[\leadsto \left(\cos \varepsilon \cdot \cos x - \color{blue}{1 \cdot \cos x}\right) - \sin \varepsilon \cdot \sin x \]
      3. distribute-rgt-out--98.9%

        \[\leadsto \color{blue}{\cos x \cdot \left(\cos \varepsilon - 1\right)} - \sin \varepsilon \cdot \sin x \]
      4. sub-neg98.9%

        \[\leadsto \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)} - \sin \varepsilon \cdot \sin x \]
      5. metadata-eval98.9%

        \[\leadsto \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right) - \sin \varepsilon \cdot \sin x \]
      6. +-commutative98.9%

        \[\leadsto \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)} - \sin \varepsilon \cdot \sin x \]
      7. *-commutative98.9%

        \[\leadsto \cos x \cdot \left(-1 + \cos \varepsilon\right) - \color{blue}{\sin x \cdot \sin \varepsilon} \]
    8. Simplified98.9%

      \[\leadsto \color{blue}{\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin x \cdot \sin \varepsilon} \]
    9. Step-by-step derivation
      1. distribute-lft-in99.1%

        \[\leadsto \color{blue}{\left(\cos x \cdot -1 + \cos x \cdot \cos \varepsilon\right)} - \sin x \cdot \sin \varepsilon \]
    10. Applied egg-rr99.1%

      \[\leadsto \color{blue}{\left(\cos x \cdot -1 + \cos x \cdot \cos \varepsilon\right)} - \sin x \cdot \sin \varepsilon \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.004:\\ \;\;\;\;\mathsf{fma}\left(\cos x, \cos \varepsilon, \sin \varepsilon \cdot \left(-\sin x\right)\right) - \cos x\\ \mathbf{elif}\;\varepsilon \leq 0.004:\\ \;\;\;\;\left(\sin x \cdot \left(-0.125 \cdot \left(\varepsilon \cdot \varepsilon\right) + 1\right) + \cos x \cdot \left(\varepsilon \cdot 0.5 + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\ \end{array} \]

Alternative 2: 99.0% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \cos x \cdot \frac{{\sin \varepsilon}^{2}}{-1 - \cos \varepsilon} - \sin \varepsilon \cdot \sin x \end{array} \]
(FPCore (x eps)
 :precision binary64
 (-
  (* (cos x) (/ (pow (sin eps) 2.0) (- -1.0 (cos eps))))
  (* (sin eps) (sin x))))
double code(double x, double eps) {
	return (cos(x) * (pow(sin(eps), 2.0) / (-1.0 - cos(eps)))) - (sin(eps) * sin(x));
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = (cos(x) * ((sin(eps) ** 2.0d0) / ((-1.0d0) - cos(eps)))) - (sin(eps) * sin(x))
end function
public static double code(double x, double eps) {
	return (Math.cos(x) * (Math.pow(Math.sin(eps), 2.0) / (-1.0 - Math.cos(eps)))) - (Math.sin(eps) * Math.sin(x));
}
def code(x, eps):
	return (math.cos(x) * (math.pow(math.sin(eps), 2.0) / (-1.0 - math.cos(eps)))) - (math.sin(eps) * math.sin(x))
function code(x, eps)
	return Float64(Float64(cos(x) * Float64((sin(eps) ^ 2.0) / Float64(-1.0 - cos(eps)))) - Float64(sin(eps) * sin(x)))
end
function tmp = code(x, eps)
	tmp = (cos(x) * ((sin(eps) ^ 2.0) / (-1.0 - cos(eps)))) - (sin(eps) * sin(x));
end
code[x_, eps_] := N[(N[(N[Cos[x], $MachinePrecision] * N[(N[Power[N[Sin[eps], $MachinePrecision], 2.0], $MachinePrecision] / N[(-1.0 - N[Cos[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\cos x \cdot \frac{{\sin \varepsilon}^{2}}{-1 - \cos \varepsilon} - \sin \varepsilon \cdot \sin x
\end{array}
Derivation
  1. Initial program 36.8%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Step-by-step derivation
    1. sub-neg36.8%

      \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
    2. cos-sum61.5%

      \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} + \left(-\cos x\right) \]
    3. associate-+l-61.5%

      \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
    4. fma-neg61.5%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
  3. Applied egg-rr61.5%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
  4. Step-by-step derivation
    1. fma-neg61.5%

      \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
    2. *-commutative61.5%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x} - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right) \]
    3. *-commutative61.5%

      \[\leadsto \cos \varepsilon \cdot \cos x - \left(\color{blue}{\sin \varepsilon \cdot \sin x} - \left(-\cos x\right)\right) \]
    4. fma-neg61.5%

      \[\leadsto \cos \varepsilon \cdot \cos x - \color{blue}{\mathsf{fma}\left(\sin \varepsilon, \sin x, -\left(-\cos x\right)\right)} \]
    5. remove-double-neg61.5%

      \[\leadsto \cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \color{blue}{\cos x}\right) \]
  5. Simplified61.5%

    \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)} \]
  6. Taylor expanded in eps around inf 61.5%

    \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \left(\cos x + \sin \varepsilon \cdot \sin x\right)} \]
  7. Step-by-step derivation
    1. associate--r+89.4%

      \[\leadsto \color{blue}{\left(\cos \varepsilon \cdot \cos x - \cos x\right) - \sin \varepsilon \cdot \sin x} \]
    2. *-lft-identity89.4%

      \[\leadsto \left(\cos \varepsilon \cdot \cos x - \color{blue}{1 \cdot \cos x}\right) - \sin \varepsilon \cdot \sin x \]
    3. distribute-rgt-out--89.4%

      \[\leadsto \color{blue}{\cos x \cdot \left(\cos \varepsilon - 1\right)} - \sin \varepsilon \cdot \sin x \]
    4. sub-neg89.4%

      \[\leadsto \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)} - \sin \varepsilon \cdot \sin x \]
    5. metadata-eval89.4%

      \[\leadsto \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right) - \sin \varepsilon \cdot \sin x \]
    6. +-commutative89.4%

      \[\leadsto \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)} - \sin \varepsilon \cdot \sin x \]
    7. *-commutative89.4%

      \[\leadsto \cos x \cdot \left(-1 + \cos \varepsilon\right) - \color{blue}{\sin x \cdot \sin \varepsilon} \]
  8. Simplified89.4%

    \[\leadsto \color{blue}{\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin x \cdot \sin \varepsilon} \]
  9. Step-by-step derivation
    1. flip-+89.0%

      \[\leadsto \cos x \cdot \color{blue}{\frac{-1 \cdot -1 - \cos \varepsilon \cdot \cos \varepsilon}{-1 - \cos \varepsilon}} - \sin x \cdot \sin \varepsilon \]
    2. metadata-eval89.0%

      \[\leadsto \cos x \cdot \frac{\color{blue}{1} - \cos \varepsilon \cdot \cos \varepsilon}{-1 - \cos \varepsilon} - \sin x \cdot \sin \varepsilon \]
    3. 1-sub-cos98.9%

      \[\leadsto \cos x \cdot \frac{\color{blue}{\sin \varepsilon \cdot \sin \varepsilon}}{-1 - \cos \varepsilon} - \sin x \cdot \sin \varepsilon \]
    4. pow298.9%

      \[\leadsto \cos x \cdot \frac{\color{blue}{{\sin \varepsilon}^{2}}}{-1 - \cos \varepsilon} - \sin x \cdot \sin \varepsilon \]
  10. Applied egg-rr98.9%

    \[\leadsto \cos x \cdot \color{blue}{\frac{{\sin \varepsilon}^{2}}{-1 - \cos \varepsilon}} - \sin x \cdot \sin \varepsilon \]
  11. Final simplification98.9%

    \[\leadsto \cos x \cdot \frac{{\sin \varepsilon}^{2}}{-1 - \cos \varepsilon} - \sin \varepsilon \cdot \sin x \]

Alternative 3: 99.3% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0039:\\ \;\;\;\;\mathsf{fma}\left(-1 + \cos \varepsilon, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)\\ \mathbf{elif}\;\varepsilon \leq 0.0039:\\ \;\;\;\;\left(\sin x \cdot \left(-0.125 \cdot \left(\varepsilon \cdot \varepsilon\right) + 1\right) + \cos x \cdot \left(\varepsilon \cdot 0.5 + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -0.0039)
   (fma (+ -1.0 (cos eps)) (cos x) (* (sin eps) (- (sin x))))
   (if (<= eps 0.0039)
     (*
      (+
       (* (sin x) (+ (* -0.125 (* eps eps)) 1.0))
       (* (cos x) (+ (* eps 0.5) (* -0.020833333333333332 (pow eps 3.0)))))
      (* -2.0 (sin (* eps 0.5))))
     (- (- (* (cos x) (cos eps)) (cos x)) (* (sin eps) (sin x))))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -0.0039) {
		tmp = fma((-1.0 + cos(eps)), cos(x), (sin(eps) * -sin(x)));
	} else if (eps <= 0.0039) {
		tmp = ((sin(x) * ((-0.125 * (eps * eps)) + 1.0)) + (cos(x) * ((eps * 0.5) + (-0.020833333333333332 * pow(eps, 3.0))))) * (-2.0 * sin((eps * 0.5)));
	} else {
		tmp = ((cos(x) * cos(eps)) - cos(x)) - (sin(eps) * sin(x));
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if (eps <= -0.0039)
		tmp = fma(Float64(-1.0 + cos(eps)), cos(x), Float64(sin(eps) * Float64(-sin(x))));
	elseif (eps <= 0.0039)
		tmp = Float64(Float64(Float64(sin(x) * Float64(Float64(-0.125 * Float64(eps * eps)) + 1.0)) + Float64(cos(x) * Float64(Float64(eps * 0.5) + Float64(-0.020833333333333332 * (eps ^ 3.0))))) * Float64(-2.0 * sin(Float64(eps * 0.5))));
	else
		tmp = Float64(Float64(Float64(cos(x) * cos(eps)) - cos(x)) - Float64(sin(eps) * sin(x)));
	end
	return tmp
end
code[x_, eps_] := If[LessEqual[eps, -0.0039], N[(N[(-1.0 + N[Cos[eps], $MachinePrecision]), $MachinePrecision] * N[Cos[x], $MachinePrecision] + N[(N[Sin[eps], $MachinePrecision] * (-N[Sin[x], $MachinePrecision])), $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 0.0039], N[(N[(N[(N[Sin[x], $MachinePrecision] * N[(N[(-0.125 * N[(eps * eps), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision] + N[(N[Cos[x], $MachinePrecision] * N[(N[(eps * 0.5), $MachinePrecision] + N[(-0.020833333333333332 * N[Power[eps, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(-2.0 * N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[(N[Cos[x], $MachinePrecision] * N[Cos[eps], $MachinePrecision]), $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision] - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.0039:\\
\;\;\;\;\mathsf{fma}\left(-1 + \cos \varepsilon, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)\\

\mathbf{elif}\;\varepsilon \leq 0.0039:\\
\;\;\;\;\left(\sin x \cdot \left(-0.125 \cdot \left(\varepsilon \cdot \varepsilon\right) + 1\right) + \cos x \cdot \left(\varepsilon \cdot 0.5 + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -0.0038999999999999998

    1. Initial program 46.5%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg46.5%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum98.5%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} + \left(-\cos x\right) \]
      3. associate-+l-98.4%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      4. fma-neg98.4%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    3. Applied egg-rr98.4%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    4. Step-by-step derivation
      1. fma-neg98.4%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      2. *-commutative98.4%

        \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x} - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right) \]
      3. *-commutative98.4%

        \[\leadsto \cos \varepsilon \cdot \cos x - \left(\color{blue}{\sin \varepsilon \cdot \sin x} - \left(-\cos x\right)\right) \]
      4. fma-neg98.5%

        \[\leadsto \cos \varepsilon \cdot \cos x - \color{blue}{\mathsf{fma}\left(\sin \varepsilon, \sin x, -\left(-\cos x\right)\right)} \]
      5. remove-double-neg98.5%

        \[\leadsto \cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \color{blue}{\cos x}\right) \]
    5. Simplified98.5%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)} \]
    6. Taylor expanded in eps around inf 98.4%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \left(\cos x + \sin \varepsilon \cdot \sin x\right)} \]
    7. Step-by-step derivation
      1. associate--r+98.4%

        \[\leadsto \color{blue}{\left(\cos \varepsilon \cdot \cos x - \cos x\right) - \sin \varepsilon \cdot \sin x} \]
      2. *-lft-identity98.4%

        \[\leadsto \left(\cos \varepsilon \cdot \cos x - \color{blue}{1 \cdot \cos x}\right) - \sin \varepsilon \cdot \sin x \]
      3. distribute-rgt-out--98.5%

        \[\leadsto \color{blue}{\cos x \cdot \left(\cos \varepsilon - 1\right)} - \sin \varepsilon \cdot \sin x \]
      4. sub-neg98.5%

        \[\leadsto \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)} - \sin \varepsilon \cdot \sin x \]
      5. metadata-eval98.5%

        \[\leadsto \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right) - \sin \varepsilon \cdot \sin x \]
      6. +-commutative98.5%

        \[\leadsto \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)} - \sin \varepsilon \cdot \sin x \]
      7. *-commutative98.5%

        \[\leadsto \cos x \cdot \left(-1 + \cos \varepsilon\right) - \color{blue}{\sin x \cdot \sin \varepsilon} \]
    8. Simplified98.5%

      \[\leadsto \color{blue}{\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin x \cdot \sin \varepsilon} \]
    9. Step-by-step derivation
      1. cancel-sign-sub-inv98.5%

        \[\leadsto \color{blue}{\cos x \cdot \left(-1 + \cos \varepsilon\right) + \left(-\sin x\right) \cdot \sin \varepsilon} \]
      2. *-commutative98.5%

        \[\leadsto \color{blue}{\left(-1 + \cos \varepsilon\right) \cdot \cos x} + \left(-\sin x\right) \cdot \sin \varepsilon \]
      3. fma-def98.5%

        \[\leadsto \color{blue}{\mathsf{fma}\left(-1 + \cos \varepsilon, \cos x, \left(-\sin x\right) \cdot \sin \varepsilon\right)} \]
    10. Applied egg-rr98.5%

      \[\leadsto \color{blue}{\mathsf{fma}\left(-1 + \cos \varepsilon, \cos x, \left(-\sin x\right) \cdot \sin \varepsilon\right)} \]

    if -0.0038999999999999998 < eps < 0.0038999999999999998

    1. Initial program 21.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos41.4%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv41.4%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. associate--l+41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\color{blue}{\left(x + \left(\varepsilon - x\right)\right)} \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. metadata-eval41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      5. div-inv41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      6. +-commutative41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} + x\right) \cdot \frac{1}{2}\right)\right) \]
      7. associate-+l+41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(\varepsilon + \left(x + x\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      8. metadata-eval41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr41.4%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. associate-*r*41.4%

        \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)} \]
      2. *-commutative41.4%

        \[\leadsto \color{blue}{\sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right)} \]
      3. *-commutative41.4%

        \[\leadsto \sin \color{blue}{\left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      4. +-commutative41.4%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      5. count-241.4%

        \[\leadsto \sin \left(0.5 \cdot \left(\color{blue}{2 \cdot x} + \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      6. fma-def41.4%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\mathsf{fma}\left(2, x, \varepsilon\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      7. sub-neg41.4%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \color{blue}{\left(\varepsilon + \left(-x\right)\right)}\right) \cdot 0.5\right)\right) \]
      8. mul-1-neg41.4%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon + \color{blue}{-1 \cdot x}\right)\right) \cdot 0.5\right)\right) \]
      9. +-commutative41.4%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \color{blue}{\left(-1 \cdot x + \varepsilon\right)}\right) \cdot 0.5\right)\right) \]
      10. associate-+r+99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(\left(x + -1 \cdot x\right) + \varepsilon\right)} \cdot 0.5\right)\right) \]
      11. mul-1-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\left(x + \color{blue}{\left(-x\right)}\right) + \varepsilon\right) \cdot 0.5\right)\right) \]
      12. sub-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\color{blue}{\left(x - x\right)} + \varepsilon\right) \cdot 0.5\right)\right) \]
      13. +-inverses99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\color{blue}{0} + \varepsilon\right) \cdot 0.5\right)\right) \]
      14. remove-double-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(0 + \color{blue}{\left(-\left(-\varepsilon\right)\right)}\right) \cdot 0.5\right)\right) \]
      15. mul-1-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(0 + \left(-\color{blue}{-1 \cdot \varepsilon}\right)\right) \cdot 0.5\right)\right) \]
      16. sub-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(0 - -1 \cdot \varepsilon\right)} \cdot 0.5\right)\right) \]
      17. neg-sub099.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(--1 \cdot \varepsilon\right)} \cdot 0.5\right)\right) \]
      18. mul-1-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(-\color{blue}{\left(-\varepsilon\right)}\right) \cdot 0.5\right)\right) \]
      19. remove-double-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\varepsilon} \cdot 0.5\right)\right) \]
    5. Simplified99.0%

      \[\leadsto \color{blue}{\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)} \]
    6. Taylor expanded in eps around 0 99.8%

      \[\leadsto \color{blue}{\left(\sin x + \left(-0.125 \cdot \left({\varepsilon}^{2} \cdot \sin x\right) + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    7. Step-by-step derivation
      1. associate-+r+99.8%

        \[\leadsto \color{blue}{\left(\left(\sin x + -0.125 \cdot \left({\varepsilon}^{2} \cdot \sin x\right)\right) + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      2. associate-*r*99.8%

        \[\leadsto \left(\left(\sin x + \color{blue}{\left(-0.125 \cdot {\varepsilon}^{2}\right) \cdot \sin x}\right) + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      3. distribute-rgt1-in99.8%

        \[\leadsto \left(\color{blue}{\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x} + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      4. +-commutative99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \color{blue}{\left(0.5 \cdot \left(\varepsilon \cdot \cos x\right) + -0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right)\right)}\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      5. associate-*r*99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \left(\color{blue}{\left(0.5 \cdot \varepsilon\right) \cdot \cos x} + -0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right)\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      6. associate-*r*99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \left(\left(0.5 \cdot \varepsilon\right) \cdot \cos x + \color{blue}{\left(-0.020833333333333332 \cdot {\varepsilon}^{3}\right) \cdot \cos x}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      7. distribute-rgt-out99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \color{blue}{\cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)}\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    8. Simplified99.8%

      \[\leadsto \color{blue}{\left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right)} \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    9. Step-by-step derivation
      1. unpow299.8%

        \[\leadsto \left(\left(-0.125 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    10. Applied egg-rr99.8%

      \[\leadsto \left(\left(-0.125 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]

    if 0.0038999999999999998 < eps

    1. Initial program 56.2%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg56.2%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum98.9%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} + \left(-\cos x\right) \]
      3. associate-+l-98.8%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      4. fma-neg98.9%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    3. Applied egg-rr98.9%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    4. Step-by-step derivation
      1. fma-neg98.8%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      2. *-commutative98.8%

        \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x} - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right) \]
      3. *-commutative98.8%

        \[\leadsto \cos \varepsilon \cdot \cos x - \left(\color{blue}{\sin \varepsilon \cdot \sin x} - \left(-\cos x\right)\right) \]
      4. fma-neg98.9%

        \[\leadsto \cos \varepsilon \cdot \cos x - \color{blue}{\mathsf{fma}\left(\sin \varepsilon, \sin x, -\left(-\cos x\right)\right)} \]
      5. remove-double-neg98.9%

        \[\leadsto \cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \color{blue}{\cos x}\right) \]
    5. Simplified98.9%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)} \]
    6. Taylor expanded in eps around inf 98.8%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \left(\cos x + \sin \varepsilon \cdot \sin x\right)} \]
    7. Step-by-step derivation
      1. associate--r+99.1%

        \[\leadsto \color{blue}{\left(\cos \varepsilon \cdot \cos x - \cos x\right) - \sin \varepsilon \cdot \sin x} \]
      2. *-lft-identity99.1%

        \[\leadsto \left(\cos \varepsilon \cdot \cos x - \color{blue}{1 \cdot \cos x}\right) - \sin \varepsilon \cdot \sin x \]
      3. distribute-rgt-out--98.9%

        \[\leadsto \color{blue}{\cos x \cdot \left(\cos \varepsilon - 1\right)} - \sin \varepsilon \cdot \sin x \]
      4. sub-neg98.9%

        \[\leadsto \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)} - \sin \varepsilon \cdot \sin x \]
      5. metadata-eval98.9%

        \[\leadsto \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right) - \sin \varepsilon \cdot \sin x \]
      6. +-commutative98.9%

        \[\leadsto \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)} - \sin \varepsilon \cdot \sin x \]
      7. *-commutative98.9%

        \[\leadsto \cos x \cdot \left(-1 + \cos \varepsilon\right) - \color{blue}{\sin x \cdot \sin \varepsilon} \]
    8. Simplified98.9%

      \[\leadsto \color{blue}{\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin x \cdot \sin \varepsilon} \]
    9. Step-by-step derivation
      1. distribute-lft-in99.1%

        \[\leadsto \color{blue}{\left(\cos x \cdot -1 + \cos x \cdot \cos \varepsilon\right)} - \sin x \cdot \sin \varepsilon \]
    10. Applied egg-rr99.1%

      \[\leadsto \color{blue}{\left(\cos x \cdot -1 + \cos x \cdot \cos \varepsilon\right)} - \sin x \cdot \sin \varepsilon \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0039:\\ \;\;\;\;\mathsf{fma}\left(-1 + \cos \varepsilon, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)\\ \mathbf{elif}\;\varepsilon \leq 0.0039:\\ \;\;\;\;\left(\sin x \cdot \left(-0.125 \cdot \left(\varepsilon \cdot \varepsilon\right) + 1\right) + \cos x \cdot \left(\varepsilon \cdot 0.5 + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\cos x \cdot \cos \varepsilon - \cos x\right) - \sin \varepsilon \cdot \sin x\\ \end{array} \]

Alternative 4: 99.3% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0035 \lor \neg \left(\varepsilon \leq 0.0039\right):\\ \;\;\;\;\mathsf{fma}\left(-1 + \cos \varepsilon, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\sin x \cdot \left(-0.125 \cdot \left(\varepsilon \cdot \varepsilon\right) + 1\right) + \cos x \cdot \left(\varepsilon \cdot 0.5 + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -0.0035) (not (<= eps 0.0039)))
   (fma (+ -1.0 (cos eps)) (cos x) (* (sin eps) (- (sin x))))
   (*
    (+
     (* (sin x) (+ (* -0.125 (* eps eps)) 1.0))
     (* (cos x) (+ (* eps 0.5) (* -0.020833333333333332 (pow eps 3.0)))))
    (* -2.0 (sin (* eps 0.5))))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.0035) || !(eps <= 0.0039)) {
		tmp = fma((-1.0 + cos(eps)), cos(x), (sin(eps) * -sin(x)));
	} else {
		tmp = ((sin(x) * ((-0.125 * (eps * eps)) + 1.0)) + (cos(x) * ((eps * 0.5) + (-0.020833333333333332 * pow(eps, 3.0))))) * (-2.0 * sin((eps * 0.5)));
	}
	return tmp;
}
function code(x, eps)
	tmp = 0.0
	if ((eps <= -0.0035) || !(eps <= 0.0039))
		tmp = fma(Float64(-1.0 + cos(eps)), cos(x), Float64(sin(eps) * Float64(-sin(x))));
	else
		tmp = Float64(Float64(Float64(sin(x) * Float64(Float64(-0.125 * Float64(eps * eps)) + 1.0)) + Float64(cos(x) * Float64(Float64(eps * 0.5) + Float64(-0.020833333333333332 * (eps ^ 3.0))))) * Float64(-2.0 * sin(Float64(eps * 0.5))));
	end
	return tmp
end
code[x_, eps_] := If[Or[LessEqual[eps, -0.0035], N[Not[LessEqual[eps, 0.0039]], $MachinePrecision]], N[(N[(-1.0 + N[Cos[eps], $MachinePrecision]), $MachinePrecision] * N[Cos[x], $MachinePrecision] + N[(N[Sin[eps], $MachinePrecision] * (-N[Sin[x], $MachinePrecision])), $MachinePrecision]), $MachinePrecision], N[(N[(N[(N[Sin[x], $MachinePrecision] * N[(N[(-0.125 * N[(eps * eps), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision] + N[(N[Cos[x], $MachinePrecision] * N[(N[(eps * 0.5), $MachinePrecision] + N[(-0.020833333333333332 * N[Power[eps, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(-2.0 * N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.0035 \lor \neg \left(\varepsilon \leq 0.0039\right):\\
\;\;\;\;\mathsf{fma}\left(-1 + \cos \varepsilon, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\left(\sin x \cdot \left(-0.125 \cdot \left(\varepsilon \cdot \varepsilon\right) + 1\right) + \cos x \cdot \left(\varepsilon \cdot 0.5 + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -0.00350000000000000007 or 0.0038999999999999998 < eps

    1. Initial program 51.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg51.4%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum98.7%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} + \left(-\cos x\right) \]
      3. associate-+l-98.6%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      4. fma-neg98.7%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    3. Applied egg-rr98.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    4. Step-by-step derivation
      1. fma-neg98.6%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      2. *-commutative98.6%

        \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x} - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right) \]
      3. *-commutative98.6%

        \[\leadsto \cos \varepsilon \cdot \cos x - \left(\color{blue}{\sin \varepsilon \cdot \sin x} - \left(-\cos x\right)\right) \]
      4. fma-neg98.7%

        \[\leadsto \cos \varepsilon \cdot \cos x - \color{blue}{\mathsf{fma}\left(\sin \varepsilon, \sin x, -\left(-\cos x\right)\right)} \]
      5. remove-double-neg98.7%

        \[\leadsto \cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \color{blue}{\cos x}\right) \]
    5. Simplified98.7%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)} \]
    6. Taylor expanded in eps around inf 98.6%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \left(\cos x + \sin \varepsilon \cdot \sin x\right)} \]
    7. Step-by-step derivation
      1. associate--r+98.8%

        \[\leadsto \color{blue}{\left(\cos \varepsilon \cdot \cos x - \cos x\right) - \sin \varepsilon \cdot \sin x} \]
      2. *-lft-identity98.8%

        \[\leadsto \left(\cos \varepsilon \cdot \cos x - \color{blue}{1 \cdot \cos x}\right) - \sin \varepsilon \cdot \sin x \]
      3. distribute-rgt-out--98.7%

        \[\leadsto \color{blue}{\cos x \cdot \left(\cos \varepsilon - 1\right)} - \sin \varepsilon \cdot \sin x \]
      4. sub-neg98.7%

        \[\leadsto \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)} - \sin \varepsilon \cdot \sin x \]
      5. metadata-eval98.7%

        \[\leadsto \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right) - \sin \varepsilon \cdot \sin x \]
      6. +-commutative98.7%

        \[\leadsto \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)} - \sin \varepsilon \cdot \sin x \]
      7. *-commutative98.7%

        \[\leadsto \cos x \cdot \left(-1 + \cos \varepsilon\right) - \color{blue}{\sin x \cdot \sin \varepsilon} \]
    8. Simplified98.7%

      \[\leadsto \color{blue}{\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin x \cdot \sin \varepsilon} \]
    9. Step-by-step derivation
      1. cancel-sign-sub-inv98.7%

        \[\leadsto \color{blue}{\cos x \cdot \left(-1 + \cos \varepsilon\right) + \left(-\sin x\right) \cdot \sin \varepsilon} \]
      2. *-commutative98.7%

        \[\leadsto \color{blue}{\left(-1 + \cos \varepsilon\right) \cdot \cos x} + \left(-\sin x\right) \cdot \sin \varepsilon \]
      3. fma-def98.8%

        \[\leadsto \color{blue}{\mathsf{fma}\left(-1 + \cos \varepsilon, \cos x, \left(-\sin x\right) \cdot \sin \varepsilon\right)} \]
    10. Applied egg-rr98.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(-1 + \cos \varepsilon, \cos x, \left(-\sin x\right) \cdot \sin \varepsilon\right)} \]

    if -0.00350000000000000007 < eps < 0.0038999999999999998

    1. Initial program 21.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos41.4%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv41.4%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. associate--l+41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\color{blue}{\left(x + \left(\varepsilon - x\right)\right)} \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. metadata-eval41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      5. div-inv41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      6. +-commutative41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} + x\right) \cdot \frac{1}{2}\right)\right) \]
      7. associate-+l+41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(\varepsilon + \left(x + x\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      8. metadata-eval41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr41.4%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. associate-*r*41.4%

        \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)} \]
      2. *-commutative41.4%

        \[\leadsto \color{blue}{\sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right)} \]
      3. *-commutative41.4%

        \[\leadsto \sin \color{blue}{\left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      4. +-commutative41.4%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      5. count-241.4%

        \[\leadsto \sin \left(0.5 \cdot \left(\color{blue}{2 \cdot x} + \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      6. fma-def41.4%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\mathsf{fma}\left(2, x, \varepsilon\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      7. sub-neg41.4%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \color{blue}{\left(\varepsilon + \left(-x\right)\right)}\right) \cdot 0.5\right)\right) \]
      8. mul-1-neg41.4%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon + \color{blue}{-1 \cdot x}\right)\right) \cdot 0.5\right)\right) \]
      9. +-commutative41.4%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \color{blue}{\left(-1 \cdot x + \varepsilon\right)}\right) \cdot 0.5\right)\right) \]
      10. associate-+r+99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(\left(x + -1 \cdot x\right) + \varepsilon\right)} \cdot 0.5\right)\right) \]
      11. mul-1-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\left(x + \color{blue}{\left(-x\right)}\right) + \varepsilon\right) \cdot 0.5\right)\right) \]
      12. sub-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\color{blue}{\left(x - x\right)} + \varepsilon\right) \cdot 0.5\right)\right) \]
      13. +-inverses99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\color{blue}{0} + \varepsilon\right) \cdot 0.5\right)\right) \]
      14. remove-double-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(0 + \color{blue}{\left(-\left(-\varepsilon\right)\right)}\right) \cdot 0.5\right)\right) \]
      15. mul-1-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(0 + \left(-\color{blue}{-1 \cdot \varepsilon}\right)\right) \cdot 0.5\right)\right) \]
      16. sub-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(0 - -1 \cdot \varepsilon\right)} \cdot 0.5\right)\right) \]
      17. neg-sub099.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(--1 \cdot \varepsilon\right)} \cdot 0.5\right)\right) \]
      18. mul-1-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(-\color{blue}{\left(-\varepsilon\right)}\right) \cdot 0.5\right)\right) \]
      19. remove-double-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\varepsilon} \cdot 0.5\right)\right) \]
    5. Simplified99.0%

      \[\leadsto \color{blue}{\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)} \]
    6. Taylor expanded in eps around 0 99.8%

      \[\leadsto \color{blue}{\left(\sin x + \left(-0.125 \cdot \left({\varepsilon}^{2} \cdot \sin x\right) + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    7. Step-by-step derivation
      1. associate-+r+99.8%

        \[\leadsto \color{blue}{\left(\left(\sin x + -0.125 \cdot \left({\varepsilon}^{2} \cdot \sin x\right)\right) + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      2. associate-*r*99.8%

        \[\leadsto \left(\left(\sin x + \color{blue}{\left(-0.125 \cdot {\varepsilon}^{2}\right) \cdot \sin x}\right) + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      3. distribute-rgt1-in99.8%

        \[\leadsto \left(\color{blue}{\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x} + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      4. +-commutative99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \color{blue}{\left(0.5 \cdot \left(\varepsilon \cdot \cos x\right) + -0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right)\right)}\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      5. associate-*r*99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \left(\color{blue}{\left(0.5 \cdot \varepsilon\right) \cdot \cos x} + -0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right)\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      6. associate-*r*99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \left(\left(0.5 \cdot \varepsilon\right) \cdot \cos x + \color{blue}{\left(-0.020833333333333332 \cdot {\varepsilon}^{3}\right) \cdot \cos x}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      7. distribute-rgt-out99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \color{blue}{\cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)}\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    8. Simplified99.8%

      \[\leadsto \color{blue}{\left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right)} \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    9. Step-by-step derivation
      1. unpow299.8%

        \[\leadsto \left(\left(-0.125 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    10. Applied egg-rr99.8%

      \[\leadsto \left(\left(-0.125 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0035 \lor \neg \left(\varepsilon \leq 0.0039\right):\\ \;\;\;\;\mathsf{fma}\left(-1 + \cos \varepsilon, \cos x, \sin \varepsilon \cdot \left(-\sin x\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\sin x \cdot \left(-0.125 \cdot \left(\varepsilon \cdot \varepsilon\right) + 1\right) + \cos x \cdot \left(\varepsilon \cdot 0.5 + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \end{array} \]

Alternative 5: 99.3% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0035 \lor \neg \left(\varepsilon \leq 0.0035\right):\\ \;\;\;\;\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\left(\sin x \cdot \left(-0.125 \cdot \left(\varepsilon \cdot \varepsilon\right) + 1\right) + \cos x \cdot \left(\varepsilon \cdot 0.5 + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -0.0035) (not (<= eps 0.0035)))
   (- (* (cos x) (+ -1.0 (cos eps))) (* (sin eps) (sin x)))
   (*
    (+
     (* (sin x) (+ (* -0.125 (* eps eps)) 1.0))
     (* (cos x) (+ (* eps 0.5) (* -0.020833333333333332 (pow eps 3.0)))))
    (* -2.0 (sin (* eps 0.5))))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.0035) || !(eps <= 0.0035)) {
		tmp = (cos(x) * (-1.0 + cos(eps))) - (sin(eps) * sin(x));
	} else {
		tmp = ((sin(x) * ((-0.125 * (eps * eps)) + 1.0)) + (cos(x) * ((eps * 0.5) + (-0.020833333333333332 * pow(eps, 3.0))))) * (-2.0 * sin((eps * 0.5)));
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-0.0035d0)) .or. (.not. (eps <= 0.0035d0))) then
        tmp = (cos(x) * ((-1.0d0) + cos(eps))) - (sin(eps) * sin(x))
    else
        tmp = ((sin(x) * (((-0.125d0) * (eps * eps)) + 1.0d0)) + (cos(x) * ((eps * 0.5d0) + ((-0.020833333333333332d0) * (eps ** 3.0d0))))) * ((-2.0d0) * sin((eps * 0.5d0)))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -0.0035) || !(eps <= 0.0035)) {
		tmp = (Math.cos(x) * (-1.0 + Math.cos(eps))) - (Math.sin(eps) * Math.sin(x));
	} else {
		tmp = ((Math.sin(x) * ((-0.125 * (eps * eps)) + 1.0)) + (Math.cos(x) * ((eps * 0.5) + (-0.020833333333333332 * Math.pow(eps, 3.0))))) * (-2.0 * Math.sin((eps * 0.5)));
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -0.0035) or not (eps <= 0.0035):
		tmp = (math.cos(x) * (-1.0 + math.cos(eps))) - (math.sin(eps) * math.sin(x))
	else:
		tmp = ((math.sin(x) * ((-0.125 * (eps * eps)) + 1.0)) + (math.cos(x) * ((eps * 0.5) + (-0.020833333333333332 * math.pow(eps, 3.0))))) * (-2.0 * math.sin((eps * 0.5)))
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -0.0035) || !(eps <= 0.0035))
		tmp = Float64(Float64(cos(x) * Float64(-1.0 + cos(eps))) - Float64(sin(eps) * sin(x)));
	else
		tmp = Float64(Float64(Float64(sin(x) * Float64(Float64(-0.125 * Float64(eps * eps)) + 1.0)) + Float64(cos(x) * Float64(Float64(eps * 0.5) + Float64(-0.020833333333333332 * (eps ^ 3.0))))) * Float64(-2.0 * sin(Float64(eps * 0.5))));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -0.0035) || ~((eps <= 0.0035)))
		tmp = (cos(x) * (-1.0 + cos(eps))) - (sin(eps) * sin(x));
	else
		tmp = ((sin(x) * ((-0.125 * (eps * eps)) + 1.0)) + (cos(x) * ((eps * 0.5) + (-0.020833333333333332 * (eps ^ 3.0))))) * (-2.0 * sin((eps * 0.5)));
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -0.0035], N[Not[LessEqual[eps, 0.0035]], $MachinePrecision]], N[(N[(N[Cos[x], $MachinePrecision] * N[(-1.0 + N[Cos[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[(N[Sin[x], $MachinePrecision] * N[(N[(-0.125 * N[(eps * eps), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision] + N[(N[Cos[x], $MachinePrecision] * N[(N[(eps * 0.5), $MachinePrecision] + N[(-0.020833333333333332 * N[Power[eps, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(-2.0 * N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -0.0035 \lor \neg \left(\varepsilon \leq 0.0035\right):\\
\;\;\;\;\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin \varepsilon \cdot \sin x\\

\mathbf{else}:\\
\;\;\;\;\left(\sin x \cdot \left(-0.125 \cdot \left(\varepsilon \cdot \varepsilon\right) + 1\right) + \cos x \cdot \left(\varepsilon \cdot 0.5 + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -0.00350000000000000007 or 0.00350000000000000007 < eps

    1. Initial program 51.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg51.4%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum98.7%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} + \left(-\cos x\right) \]
      3. associate-+l-98.6%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      4. fma-neg98.7%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    3. Applied egg-rr98.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    4. Step-by-step derivation
      1. fma-neg98.6%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      2. *-commutative98.6%

        \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x} - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right) \]
      3. *-commutative98.6%

        \[\leadsto \cos \varepsilon \cdot \cos x - \left(\color{blue}{\sin \varepsilon \cdot \sin x} - \left(-\cos x\right)\right) \]
      4. fma-neg98.7%

        \[\leadsto \cos \varepsilon \cdot \cos x - \color{blue}{\mathsf{fma}\left(\sin \varepsilon, \sin x, -\left(-\cos x\right)\right)} \]
      5. remove-double-neg98.7%

        \[\leadsto \cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \color{blue}{\cos x}\right) \]
    5. Simplified98.7%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)} \]
    6. Taylor expanded in eps around inf 98.6%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \left(\cos x + \sin \varepsilon \cdot \sin x\right)} \]
    7. Step-by-step derivation
      1. associate--r+98.8%

        \[\leadsto \color{blue}{\left(\cos \varepsilon \cdot \cos x - \cos x\right) - \sin \varepsilon \cdot \sin x} \]
      2. *-lft-identity98.8%

        \[\leadsto \left(\cos \varepsilon \cdot \cos x - \color{blue}{1 \cdot \cos x}\right) - \sin \varepsilon \cdot \sin x \]
      3. distribute-rgt-out--98.7%

        \[\leadsto \color{blue}{\cos x \cdot \left(\cos \varepsilon - 1\right)} - \sin \varepsilon \cdot \sin x \]
      4. sub-neg98.7%

        \[\leadsto \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)} - \sin \varepsilon \cdot \sin x \]
      5. metadata-eval98.7%

        \[\leadsto \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right) - \sin \varepsilon \cdot \sin x \]
      6. +-commutative98.7%

        \[\leadsto \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)} - \sin \varepsilon \cdot \sin x \]
      7. *-commutative98.7%

        \[\leadsto \cos x \cdot \left(-1 + \cos \varepsilon\right) - \color{blue}{\sin x \cdot \sin \varepsilon} \]
    8. Simplified98.7%

      \[\leadsto \color{blue}{\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin x \cdot \sin \varepsilon} \]

    if -0.00350000000000000007 < eps < 0.00350000000000000007

    1. Initial program 21.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos41.4%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv41.4%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. associate--l+41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\color{blue}{\left(x + \left(\varepsilon - x\right)\right)} \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. metadata-eval41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      5. div-inv41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      6. +-commutative41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} + x\right) \cdot \frac{1}{2}\right)\right) \]
      7. associate-+l+41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(\varepsilon + \left(x + x\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      8. metadata-eval41.4%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr41.4%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. associate-*r*41.4%

        \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)} \]
      2. *-commutative41.4%

        \[\leadsto \color{blue}{\sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right)} \]
      3. *-commutative41.4%

        \[\leadsto \sin \color{blue}{\left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      4. +-commutative41.4%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      5. count-241.4%

        \[\leadsto \sin \left(0.5 \cdot \left(\color{blue}{2 \cdot x} + \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      6. fma-def41.4%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\mathsf{fma}\left(2, x, \varepsilon\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      7. sub-neg41.4%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \color{blue}{\left(\varepsilon + \left(-x\right)\right)}\right) \cdot 0.5\right)\right) \]
      8. mul-1-neg41.4%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon + \color{blue}{-1 \cdot x}\right)\right) \cdot 0.5\right)\right) \]
      9. +-commutative41.4%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \color{blue}{\left(-1 \cdot x + \varepsilon\right)}\right) \cdot 0.5\right)\right) \]
      10. associate-+r+99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(\left(x + -1 \cdot x\right) + \varepsilon\right)} \cdot 0.5\right)\right) \]
      11. mul-1-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\left(x + \color{blue}{\left(-x\right)}\right) + \varepsilon\right) \cdot 0.5\right)\right) \]
      12. sub-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\color{blue}{\left(x - x\right)} + \varepsilon\right) \cdot 0.5\right)\right) \]
      13. +-inverses99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\color{blue}{0} + \varepsilon\right) \cdot 0.5\right)\right) \]
      14. remove-double-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(0 + \color{blue}{\left(-\left(-\varepsilon\right)\right)}\right) \cdot 0.5\right)\right) \]
      15. mul-1-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(0 + \left(-\color{blue}{-1 \cdot \varepsilon}\right)\right) \cdot 0.5\right)\right) \]
      16. sub-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(0 - -1 \cdot \varepsilon\right)} \cdot 0.5\right)\right) \]
      17. neg-sub099.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(--1 \cdot \varepsilon\right)} \cdot 0.5\right)\right) \]
      18. mul-1-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(-\color{blue}{\left(-\varepsilon\right)}\right) \cdot 0.5\right)\right) \]
      19. remove-double-neg99.0%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\varepsilon} \cdot 0.5\right)\right) \]
    5. Simplified99.0%

      \[\leadsto \color{blue}{\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)} \]
    6. Taylor expanded in eps around 0 99.8%

      \[\leadsto \color{blue}{\left(\sin x + \left(-0.125 \cdot \left({\varepsilon}^{2} \cdot \sin x\right) + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    7. Step-by-step derivation
      1. associate-+r+99.8%

        \[\leadsto \color{blue}{\left(\left(\sin x + -0.125 \cdot \left({\varepsilon}^{2} \cdot \sin x\right)\right) + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      2. associate-*r*99.8%

        \[\leadsto \left(\left(\sin x + \color{blue}{\left(-0.125 \cdot {\varepsilon}^{2}\right) \cdot \sin x}\right) + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      3. distribute-rgt1-in99.8%

        \[\leadsto \left(\color{blue}{\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x} + \left(-0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right) + 0.5 \cdot \left(\varepsilon \cdot \cos x\right)\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      4. +-commutative99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \color{blue}{\left(0.5 \cdot \left(\varepsilon \cdot \cos x\right) + -0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right)\right)}\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      5. associate-*r*99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \left(\color{blue}{\left(0.5 \cdot \varepsilon\right) \cdot \cos x} + -0.020833333333333332 \cdot \left({\varepsilon}^{3} \cdot \cos x\right)\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      6. associate-*r*99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \left(\left(0.5 \cdot \varepsilon\right) \cdot \cos x + \color{blue}{\left(-0.020833333333333332 \cdot {\varepsilon}^{3}\right) \cdot \cos x}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
      7. distribute-rgt-out99.8%

        \[\leadsto \left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \color{blue}{\cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)}\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    8. Simplified99.8%

      \[\leadsto \color{blue}{\left(\left(-0.125 \cdot {\varepsilon}^{2} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right)} \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    9. Step-by-step derivation
      1. unpow299.8%

        \[\leadsto \left(\left(-0.125 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    10. Applied egg-rr99.8%

      \[\leadsto \left(\left(-0.125 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -0.0035 \lor \neg \left(\varepsilon \leq 0.0035\right):\\ \;\;\;\;\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\left(\sin x \cdot \left(-0.125 \cdot \left(\varepsilon \cdot \varepsilon\right) + 1\right) + \cos x \cdot \left(\varepsilon \cdot 0.5 + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)\\ \end{array} \]

Alternative 6: 98.8% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -3.4 \lor \neg \left(x \leq 1.3 \cdot 10^{-28}\right):\\ \;\;\;\;\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\left(-2 \cdot \sin \left(\frac{\varepsilon}{2}\right)\right) \cdot \sin \left(\frac{\varepsilon + x \cdot 2}{2}\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= x -3.4) (not (<= x 1.3e-28)))
   (- (* (cos x) (+ -1.0 (cos eps))) (* (sin eps) (sin x)))
   (* (* -2.0 (sin (/ eps 2.0))) (sin (/ (+ eps (* x 2.0)) 2.0)))))
double code(double x, double eps) {
	double tmp;
	if ((x <= -3.4) || !(x <= 1.3e-28)) {
		tmp = (cos(x) * (-1.0 + cos(eps))) - (sin(eps) * sin(x));
	} else {
		tmp = (-2.0 * sin((eps / 2.0))) * sin(((eps + (x * 2.0)) / 2.0));
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((x <= (-3.4d0)) .or. (.not. (x <= 1.3d-28))) then
        tmp = (cos(x) * ((-1.0d0) + cos(eps))) - (sin(eps) * sin(x))
    else
        tmp = ((-2.0d0) * sin((eps / 2.0d0))) * sin(((eps + (x * 2.0d0)) / 2.0d0))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((x <= -3.4) || !(x <= 1.3e-28)) {
		tmp = (Math.cos(x) * (-1.0 + Math.cos(eps))) - (Math.sin(eps) * Math.sin(x));
	} else {
		tmp = (-2.0 * Math.sin((eps / 2.0))) * Math.sin(((eps + (x * 2.0)) / 2.0));
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (x <= -3.4) or not (x <= 1.3e-28):
		tmp = (math.cos(x) * (-1.0 + math.cos(eps))) - (math.sin(eps) * math.sin(x))
	else:
		tmp = (-2.0 * math.sin((eps / 2.0))) * math.sin(((eps + (x * 2.0)) / 2.0))
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((x <= -3.4) || !(x <= 1.3e-28))
		tmp = Float64(Float64(cos(x) * Float64(-1.0 + cos(eps))) - Float64(sin(eps) * sin(x)));
	else
		tmp = Float64(Float64(-2.0 * sin(Float64(eps / 2.0))) * sin(Float64(Float64(eps + Float64(x * 2.0)) / 2.0)));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((x <= -3.4) || ~((x <= 1.3e-28)))
		tmp = (cos(x) * (-1.0 + cos(eps))) - (sin(eps) * sin(x));
	else
		tmp = (-2.0 * sin((eps / 2.0))) * sin(((eps + (x * 2.0)) / 2.0));
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[x, -3.4], N[Not[LessEqual[x, 1.3e-28]], $MachinePrecision]], N[(N[(N[Cos[x], $MachinePrecision] * N[(-1.0 + N[Cos[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(N[Sin[eps], $MachinePrecision] * N[Sin[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(-2.0 * N[Sin[N[(eps / 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[Sin[N[(N[(eps + N[(x * 2.0), $MachinePrecision]), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -3.4 \lor \neg \left(x \leq 1.3 \cdot 10^{-28}\right):\\
\;\;\;\;\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin \varepsilon \cdot \sin x\\

\mathbf{else}:\\
\;\;\;\;\left(-2 \cdot \sin \left(\frac{\varepsilon}{2}\right)\right) \cdot \sin \left(\frac{\varepsilon + x \cdot 2}{2}\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < -3.39999999999999991 or 1.3e-28 < x

    1. Initial program 8.8%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. sub-neg8.8%

        \[\leadsto \color{blue}{\cos \left(x + \varepsilon\right) + \left(-\cos x\right)} \]
      2. cos-sum56.8%

        \[\leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} + \left(-\cos x\right) \]
      3. associate-+l-56.7%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      4. fma-neg56.8%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    3. Applied egg-rr56.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\cos x, \cos \varepsilon, -\left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)\right)} \]
    4. Step-by-step derivation
      1. fma-neg56.7%

        \[\leadsto \color{blue}{\cos x \cdot \cos \varepsilon - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right)} \]
      2. *-commutative56.7%

        \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x} - \left(\sin x \cdot \sin \varepsilon - \left(-\cos x\right)\right) \]
      3. *-commutative56.7%

        \[\leadsto \cos \varepsilon \cdot \cos x - \left(\color{blue}{\sin \varepsilon \cdot \sin x} - \left(-\cos x\right)\right) \]
      4. fma-neg56.8%

        \[\leadsto \cos \varepsilon \cdot \cos x - \color{blue}{\mathsf{fma}\left(\sin \varepsilon, \sin x, -\left(-\cos x\right)\right)} \]
      5. remove-double-neg56.8%

        \[\leadsto \cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \color{blue}{\cos x}\right) \]
    5. Simplified56.8%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \mathsf{fma}\left(\sin \varepsilon, \sin x, \cos x\right)} \]
    6. Taylor expanded in eps around inf 56.7%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \cos x - \left(\cos x + \sin \varepsilon \cdot \sin x\right)} \]
    7. Step-by-step derivation
      1. associate--r+98.7%

        \[\leadsto \color{blue}{\left(\cos \varepsilon \cdot \cos x - \cos x\right) - \sin \varepsilon \cdot \sin x} \]
      2. *-lft-identity98.7%

        \[\leadsto \left(\cos \varepsilon \cdot \cos x - \color{blue}{1 \cdot \cos x}\right) - \sin \varepsilon \cdot \sin x \]
      3. distribute-rgt-out--98.7%

        \[\leadsto \color{blue}{\cos x \cdot \left(\cos \varepsilon - 1\right)} - \sin \varepsilon \cdot \sin x \]
      4. sub-neg98.7%

        \[\leadsto \cos x \cdot \color{blue}{\left(\cos \varepsilon + \left(-1\right)\right)} - \sin \varepsilon \cdot \sin x \]
      5. metadata-eval98.7%

        \[\leadsto \cos x \cdot \left(\cos \varepsilon + \color{blue}{-1}\right) - \sin \varepsilon \cdot \sin x \]
      6. +-commutative98.7%

        \[\leadsto \cos x \cdot \color{blue}{\left(-1 + \cos \varepsilon\right)} - \sin \varepsilon \cdot \sin x \]
      7. *-commutative98.7%

        \[\leadsto \cos x \cdot \left(-1 + \cos \varepsilon\right) - \color{blue}{\sin x \cdot \sin \varepsilon} \]
    8. Simplified98.7%

      \[\leadsto \color{blue}{\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin x \cdot \sin \varepsilon} \]

    if -3.39999999999999991 < x < 1.3e-28

    1. Initial program 66.5%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. add-log-exp66.4%

        \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
    3. Applied egg-rr66.4%

      \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
    4. Step-by-step derivation
      1. diff-cos66.4%

        \[\leadsto \log \left(e^{\color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)}}\right) \]
      2. add-log-exp87.0%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      3. +-commutative87.0%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. +-commutative87.0%

        \[\leadsto -2 \cdot \left(\sin \left(\frac{\left(\varepsilon + x\right) - x}{2}\right) \cdot \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right)\right) \]
    5. Applied egg-rr87.0%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(\varepsilon + x\right) - x}{2}\right) \cdot \sin \left(\frac{\left(\varepsilon + x\right) + x}{2}\right)\right)} \]
    6. Step-by-step derivation
      1. associate-*r*87.0%

        \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\frac{\left(\varepsilon + x\right) - x}{2}\right)\right) \cdot \sin \left(\frac{\left(\varepsilon + x\right) + x}{2}\right)} \]
      2. associate--l+99.6%

        \[\leadsto \left(-2 \cdot \sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right)\right) \cdot \sin \left(\frac{\left(\varepsilon + x\right) + x}{2}\right) \]
      3. +-inverses99.6%

        \[\leadsto \left(-2 \cdot \sin \left(\frac{\varepsilon + \color{blue}{0}}{2}\right)\right) \cdot \sin \left(\frac{\left(\varepsilon + x\right) + x}{2}\right) \]
      4. associate-+l+99.6%

        \[\leadsto \left(-2 \cdot \sin \left(\frac{\varepsilon + 0}{2}\right)\right) \cdot \sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right) \]
      5. count-299.6%

        \[\leadsto \left(-2 \cdot \sin \left(\frac{\varepsilon + 0}{2}\right)\right) \cdot \sin \left(\frac{\varepsilon + \color{blue}{2 \cdot x}}{2}\right) \]
    7. Simplified99.6%

      \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\frac{\varepsilon + 0}{2}\right)\right) \cdot \sin \left(\frac{\varepsilon + 2 \cdot x}{2}\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -3.4 \lor \neg \left(x \leq 1.3 \cdot 10^{-28}\right):\\ \;\;\;\;\cos x \cdot \left(-1 + \cos \varepsilon\right) - \sin \varepsilon \cdot \sin x\\ \mathbf{else}:\\ \;\;\;\;\left(-2 \cdot \sin \left(\frac{\varepsilon}{2}\right)\right) \cdot \sin \left(\frac{\varepsilon + x \cdot 2}{2}\right)\\ \end{array} \]

Alternative 7: 76.3% accurate, 1.0× speedup?

\[\begin{array}{l} \\ -2 \cdot \left(\sin \left(\varepsilon \cdot 0.5\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)\right) \end{array} \]
(FPCore (x eps)
 :precision binary64
 (* -2.0 (* (sin (* eps 0.5)) (sin (* 0.5 (+ eps (+ x x)))))))
double code(double x, double eps) {
	return -2.0 * (sin((eps * 0.5)) * sin((0.5 * (eps + (x + x)))));
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = (-2.0d0) * (sin((eps * 0.5d0)) * sin((0.5d0 * (eps + (x + x)))))
end function
public static double code(double x, double eps) {
	return -2.0 * (Math.sin((eps * 0.5)) * Math.sin((0.5 * (eps + (x + x)))));
}
def code(x, eps):
	return -2.0 * (math.sin((eps * 0.5)) * math.sin((0.5 * (eps + (x + x)))))
function code(x, eps)
	return Float64(-2.0 * Float64(sin(Float64(eps * 0.5)) * sin(Float64(0.5 * Float64(eps + Float64(x + x))))))
end
function tmp = code(x, eps)
	tmp = -2.0 * (sin((eps * 0.5)) * sin((0.5 * (eps + (x + x)))));
end
code[x_, eps_] := N[(-2.0 * N[(N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision] * N[Sin[N[(0.5 * N[(eps + N[(x + x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
-2 \cdot \left(\sin \left(\varepsilon \cdot 0.5\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)\right)
\end{array}
Derivation
  1. Initial program 36.8%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Step-by-step derivation
    1. diff-cos46.3%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    2. *-commutative46.3%

      \[\leadsto \color{blue}{\left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2} \]
    3. div-inv46.3%

      \[\leadsto \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2 \]
    4. associate--l+46.3%

      \[\leadsto \left(\sin \left(\color{blue}{\left(x + \left(\varepsilon - x\right)\right)} \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2 \]
    5. metadata-eval46.3%

      \[\leadsto \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \cdot -2 \]
    6. div-inv46.3%

      \[\leadsto \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \cdot -2 \]
    7. +-commutative46.3%

      \[\leadsto \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} + x\right) \cdot \frac{1}{2}\right)\right) \cdot -2 \]
    8. associate-+l+46.5%

      \[\leadsto \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(\varepsilon + \left(x + x\right)\right)} \cdot \frac{1}{2}\right)\right) \cdot -2 \]
    9. metadata-eval46.5%

      \[\leadsto \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{0.5}\right)\right) \cdot -2 \]
  3. Applied egg-rr46.5%

    \[\leadsto \color{blue}{\left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \cdot -2} \]
  4. Taylor expanded in x around 0 75.9%

    \[\leadsto \left(\sin \left(\color{blue}{\varepsilon} \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right) \cdot -2 \]
  5. Final simplification75.9%

    \[\leadsto -2 \cdot \left(\sin \left(\varepsilon \cdot 0.5\right) \cdot \sin \left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)\right) \]

Alternative 8: 76.3% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left(-2 \cdot \sin \left(\frac{\varepsilon}{2}\right)\right) \cdot \sin \left(\frac{\varepsilon + x \cdot 2}{2}\right) \end{array} \]
(FPCore (x eps)
 :precision binary64
 (* (* -2.0 (sin (/ eps 2.0))) (sin (/ (+ eps (* x 2.0)) 2.0))))
double code(double x, double eps) {
	return (-2.0 * sin((eps / 2.0))) * sin(((eps + (x * 2.0)) / 2.0));
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = ((-2.0d0) * sin((eps / 2.0d0))) * sin(((eps + (x * 2.0d0)) / 2.0d0))
end function
public static double code(double x, double eps) {
	return (-2.0 * Math.sin((eps / 2.0))) * Math.sin(((eps + (x * 2.0)) / 2.0));
}
def code(x, eps):
	return (-2.0 * math.sin((eps / 2.0))) * math.sin(((eps + (x * 2.0)) / 2.0))
function code(x, eps)
	return Float64(Float64(-2.0 * sin(Float64(eps / 2.0))) * sin(Float64(Float64(eps + Float64(x * 2.0)) / 2.0)))
end
function tmp = code(x, eps)
	tmp = (-2.0 * sin((eps / 2.0))) * sin(((eps + (x * 2.0)) / 2.0));
end
code[x_, eps_] := N[(N[(-2.0 * N[Sin[N[(eps / 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[Sin[N[(N[(eps + N[(x * 2.0), $MachinePrecision]), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(-2 \cdot \sin \left(\frac{\varepsilon}{2}\right)\right) \cdot \sin \left(\frac{\varepsilon + x \cdot 2}{2}\right)
\end{array}
Derivation
  1. Initial program 36.8%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Step-by-step derivation
    1. add-log-exp36.7%

      \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
  3. Applied egg-rr36.7%

    \[\leadsto \color{blue}{\log \left(e^{\cos \left(x + \varepsilon\right) - \cos x}\right)} \]
  4. Step-by-step derivation
    1. diff-cos36.3%

      \[\leadsto \log \left(e^{\color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)}}\right) \]
    2. add-log-exp46.3%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    3. +-commutative46.3%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    4. +-commutative46.3%

      \[\leadsto -2 \cdot \left(\sin \left(\frac{\left(\varepsilon + x\right) - x}{2}\right) \cdot \sin \left(\frac{\color{blue}{\left(\varepsilon + x\right)} + x}{2}\right)\right) \]
  5. Applied egg-rr46.3%

    \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(\varepsilon + x\right) - x}{2}\right) \cdot \sin \left(\frac{\left(\varepsilon + x\right) + x}{2}\right)\right)} \]
  6. Step-by-step derivation
    1. associate-*r*46.3%

      \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\frac{\left(\varepsilon + x\right) - x}{2}\right)\right) \cdot \sin \left(\frac{\left(\varepsilon + x\right) + x}{2}\right)} \]
    2. associate--l+75.8%

      \[\leadsto \left(-2 \cdot \sin \left(\frac{\color{blue}{\varepsilon + \left(x - x\right)}}{2}\right)\right) \cdot \sin \left(\frac{\left(\varepsilon + x\right) + x}{2}\right) \]
    3. +-inverses75.8%

      \[\leadsto \left(-2 \cdot \sin \left(\frac{\varepsilon + \color{blue}{0}}{2}\right)\right) \cdot \sin \left(\frac{\left(\varepsilon + x\right) + x}{2}\right) \]
    4. associate-+l+75.9%

      \[\leadsto \left(-2 \cdot \sin \left(\frac{\varepsilon + 0}{2}\right)\right) \cdot \sin \left(\frac{\color{blue}{\varepsilon + \left(x + x\right)}}{2}\right) \]
    5. count-275.9%

      \[\leadsto \left(-2 \cdot \sin \left(\frac{\varepsilon + 0}{2}\right)\right) \cdot \sin \left(\frac{\varepsilon + \color{blue}{2 \cdot x}}{2}\right) \]
  7. Simplified75.9%

    \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\frac{\varepsilon + 0}{2}\right)\right) \cdot \sin \left(\frac{\varepsilon + 2 \cdot x}{2}\right)} \]
  8. Final simplification75.9%

    \[\leadsto \left(-2 \cdot \sin \left(\frac{\varepsilon}{2}\right)\right) \cdot \sin \left(\frac{\varepsilon + x \cdot 2}{2}\right) \]

Alternative 9: 66.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -6.2 \cdot 10^{-58} \lor \neg \left(\varepsilon \leq 1.7 \cdot 10^{-23}\right):\\ \;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\ \mathbf{else}:\\ \;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -6.2e-58) (not (<= eps 1.7e-23)))
   (* -2.0 (pow (sin (* eps 0.5)) 2.0))
   (* eps (- (sin x)))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -6.2e-58) || !(eps <= 1.7e-23)) {
		tmp = -2.0 * pow(sin((eps * 0.5)), 2.0);
	} else {
		tmp = eps * -sin(x);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-6.2d-58)) .or. (.not. (eps <= 1.7d-23))) then
        tmp = (-2.0d0) * (sin((eps * 0.5d0)) ** 2.0d0)
    else
        tmp = eps * -sin(x)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -6.2e-58) || !(eps <= 1.7e-23)) {
		tmp = -2.0 * Math.pow(Math.sin((eps * 0.5)), 2.0);
	} else {
		tmp = eps * -Math.sin(x);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -6.2e-58) or not (eps <= 1.7e-23):
		tmp = -2.0 * math.pow(math.sin((eps * 0.5)), 2.0)
	else:
		tmp = eps * -math.sin(x)
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -6.2e-58) || !(eps <= 1.7e-23))
		tmp = Float64(-2.0 * (sin(Float64(eps * 0.5)) ^ 2.0));
	else
		tmp = Float64(eps * Float64(-sin(x)));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -6.2e-58) || ~((eps <= 1.7e-23)))
		tmp = -2.0 * (sin((eps * 0.5)) ^ 2.0);
	else
		tmp = eps * -sin(x);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -6.2e-58], N[Not[LessEqual[eps, 1.7e-23]], $MachinePrecision]], N[(-2.0 * N[Power[N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision], N[(eps * (-N[Sin[x], $MachinePrecision])), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -6.2 \cdot 10^{-58} \lor \neg \left(\varepsilon \leq 1.7 \cdot 10^{-23}\right):\\
\;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\

\mathbf{else}:\\
\;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -6.1999999999999998e-58 or 1.7e-23 < eps

    1. Initial program 46.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. diff-cos54.9%

        \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv54.9%

        \[\leadsto -2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. associate--l+54.9%

        \[\leadsto -2 \cdot \left(\sin \left(\color{blue}{\left(x + \left(\varepsilon - x\right)\right)} \cdot \frac{1}{2}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. metadata-eval54.9%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot \color{blue}{0.5}\right) \cdot \sin \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      5. div-inv54.9%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      6. +-commutative54.9%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} + x\right) \cdot \frac{1}{2}\right)\right) \]
      7. associate-+l+55.3%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\color{blue}{\left(\varepsilon + \left(x + x\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      8. metadata-eval55.3%

        \[\leadsto -2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr55.3%

      \[\leadsto \color{blue}{-2 \cdot \left(\sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. associate-*r*55.3%

        \[\leadsto \color{blue}{\left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \cdot \sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right)} \]
      2. *-commutative55.3%

        \[\leadsto \color{blue}{\sin \left(\left(\varepsilon + \left(x + x\right)\right) \cdot 0.5\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right)} \]
      3. *-commutative55.3%

        \[\leadsto \sin \color{blue}{\left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)} \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      4. +-commutative55.3%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      5. count-255.3%

        \[\leadsto \sin \left(0.5 \cdot \left(\color{blue}{2 \cdot x} + \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      6. fma-def55.3%

        \[\leadsto \sin \left(0.5 \cdot \color{blue}{\mathsf{fma}\left(2, x, \varepsilon\right)}\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon - x\right)\right) \cdot 0.5\right)\right) \]
      7. sub-neg55.3%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \color{blue}{\left(\varepsilon + \left(-x\right)\right)}\right) \cdot 0.5\right)\right) \]
      8. mul-1-neg55.3%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \left(\varepsilon + \color{blue}{-1 \cdot x}\right)\right) \cdot 0.5\right)\right) \]
      9. +-commutative55.3%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(x + \color{blue}{\left(-1 \cdot x + \varepsilon\right)}\right) \cdot 0.5\right)\right) \]
      10. associate-+r+58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(\left(x + -1 \cdot x\right) + \varepsilon\right)} \cdot 0.5\right)\right) \]
      11. mul-1-neg58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\left(x + \color{blue}{\left(-x\right)}\right) + \varepsilon\right) \cdot 0.5\right)\right) \]
      12. sub-neg58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\color{blue}{\left(x - x\right)} + \varepsilon\right) \cdot 0.5\right)\right) \]
      13. +-inverses58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(\color{blue}{0} + \varepsilon\right) \cdot 0.5\right)\right) \]
      14. remove-double-neg58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(0 + \color{blue}{\left(-\left(-\varepsilon\right)\right)}\right) \cdot 0.5\right)\right) \]
      15. mul-1-neg58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(0 + \left(-\color{blue}{-1 \cdot \varepsilon}\right)\right) \cdot 0.5\right)\right) \]
      16. sub-neg58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(0 - -1 \cdot \varepsilon\right)} \cdot 0.5\right)\right) \]
      17. neg-sub058.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\left(--1 \cdot \varepsilon\right)} \cdot 0.5\right)\right) \]
      18. mul-1-neg58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\left(-\color{blue}{\left(-\varepsilon\right)}\right) \cdot 0.5\right)\right) \]
      19. remove-double-neg58.7%

        \[\leadsto \sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\color{blue}{\varepsilon} \cdot 0.5\right)\right) \]
    5. Simplified58.7%

      \[\leadsto \color{blue}{\sin \left(0.5 \cdot \mathsf{fma}\left(2, x, \varepsilon\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right)} \]
    6. Taylor expanded in x around 0 57.1%

      \[\leadsto \color{blue}{-2 \cdot {\sin \left(0.5 \cdot \varepsilon\right)}^{2}} \]

    if -6.1999999999999998e-58 < eps < 1.7e-23

    1. Initial program 23.4%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 89.1%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. mul-1-neg89.1%

        \[\leadsto \color{blue}{-\varepsilon \cdot \sin x} \]
      2. *-commutative89.1%

        \[\leadsto -\color{blue}{\sin x \cdot \varepsilon} \]
      3. distribute-rgt-neg-in89.1%

        \[\leadsto \color{blue}{\sin x \cdot \left(-\varepsilon\right)} \]
    4. Simplified89.1%

      \[\leadsto \color{blue}{\sin x \cdot \left(-\varepsilon\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification70.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -6.2 \cdot 10^{-58} \lor \neg \left(\varepsilon \leq 1.7 \cdot 10^{-23}\right):\\ \;\;\;\;-2 \cdot {\sin \left(\varepsilon \cdot 0.5\right)}^{2}\\ \mathbf{else}:\\ \;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\ \end{array} \]

Alternative 10: 67.3% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \varepsilon - \cos x\\ \mathbf{if}\;\varepsilon \leq -12.2:\\ \;\;\;\;t_0\\ \mathbf{elif}\;\varepsilon \leq -6.2 \cdot 10^{-58}:\\ \;\;\;\;-0.5 \cdot {\varepsilon}^{2}\\ \mathbf{elif}\;\varepsilon \leq 1.65 \cdot 10^{-7}:\\ \;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\ \mathbf{else}:\\ \;\;\;\;t_0\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (- (cos eps) (cos x))))
   (if (<= eps -12.2)
     t_0
     (if (<= eps -6.2e-58)
       (* -0.5 (pow eps 2.0))
       (if (<= eps 1.65e-7) (* eps (- (sin x))) t_0)))))
double code(double x, double eps) {
	double t_0 = cos(eps) - cos(x);
	double tmp;
	if (eps <= -12.2) {
		tmp = t_0;
	} else if (eps <= -6.2e-58) {
		tmp = -0.5 * pow(eps, 2.0);
	} else if (eps <= 1.65e-7) {
		tmp = eps * -sin(x);
	} else {
		tmp = t_0;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: t_0
    real(8) :: tmp
    t_0 = cos(eps) - cos(x)
    if (eps <= (-12.2d0)) then
        tmp = t_0
    else if (eps <= (-6.2d-58)) then
        tmp = (-0.5d0) * (eps ** 2.0d0)
    else if (eps <= 1.65d-7) then
        tmp = eps * -sin(x)
    else
        tmp = t_0
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double t_0 = Math.cos(eps) - Math.cos(x);
	double tmp;
	if (eps <= -12.2) {
		tmp = t_0;
	} else if (eps <= -6.2e-58) {
		tmp = -0.5 * Math.pow(eps, 2.0);
	} else if (eps <= 1.65e-7) {
		tmp = eps * -Math.sin(x);
	} else {
		tmp = t_0;
	}
	return tmp;
}
def code(x, eps):
	t_0 = math.cos(eps) - math.cos(x)
	tmp = 0
	if eps <= -12.2:
		tmp = t_0
	elif eps <= -6.2e-58:
		tmp = -0.5 * math.pow(eps, 2.0)
	elif eps <= 1.65e-7:
		tmp = eps * -math.sin(x)
	else:
		tmp = t_0
	return tmp
function code(x, eps)
	t_0 = Float64(cos(eps) - cos(x))
	tmp = 0.0
	if (eps <= -12.2)
		tmp = t_0;
	elseif (eps <= -6.2e-58)
		tmp = Float64(-0.5 * (eps ^ 2.0));
	elseif (eps <= 1.65e-7)
		tmp = Float64(eps * Float64(-sin(x)));
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(x, eps)
	t_0 = cos(eps) - cos(x);
	tmp = 0.0;
	if (eps <= -12.2)
		tmp = t_0;
	elseif (eps <= -6.2e-58)
		tmp = -0.5 * (eps ^ 2.0);
	elseif (eps <= 1.65e-7)
		tmp = eps * -sin(x);
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := Block[{t$95$0 = N[(N[Cos[eps], $MachinePrecision] - N[Cos[x], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[eps, -12.2], t$95$0, If[LessEqual[eps, -6.2e-58], N[(-0.5 * N[Power[eps, 2.0], $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 1.65e-7], N[(eps * (-N[Sin[x], $MachinePrecision])), $MachinePrecision], t$95$0]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos \varepsilon - \cos x\\
\mathbf{if}\;\varepsilon \leq -12.2:\\
\;\;\;\;t_0\\

\mathbf{elif}\;\varepsilon \leq -6.2 \cdot 10^{-58}:\\
\;\;\;\;-0.5 \cdot {\varepsilon}^{2}\\

\mathbf{elif}\;\varepsilon \leq 1.65 \cdot 10^{-7}:\\
\;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\

\mathbf{else}:\\
\;\;\;\;t_0\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -12.199999999999999 or 1.6500000000000001e-7 < eps

    1. Initial program 51.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 55.1%

      \[\leadsto \color{blue}{\cos \varepsilon} - \cos x \]

    if -12.199999999999999 < eps < -6.1999999999999998e-58

    1. Initial program 6.5%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 8.1%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
    3. Taylor expanded in eps around 0 70.3%

      \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]

    if -6.1999999999999998e-58 < eps < 1.6500000000000001e-7

    1. Initial program 22.8%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 86.8%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. mul-1-neg86.8%

        \[\leadsto \color{blue}{-\varepsilon \cdot \sin x} \]
      2. *-commutative86.8%

        \[\leadsto -\color{blue}{\sin x \cdot \varepsilon} \]
      3. distribute-rgt-neg-in86.8%

        \[\leadsto \color{blue}{\sin x \cdot \left(-\varepsilon\right)} \]
    4. Simplified86.8%

      \[\leadsto \color{blue}{\sin x \cdot \left(-\varepsilon\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification69.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -12.2:\\ \;\;\;\;\cos \varepsilon - \cos x\\ \mathbf{elif}\;\varepsilon \leq -6.2 \cdot 10^{-58}:\\ \;\;\;\;-0.5 \cdot {\varepsilon}^{2}\\ \mathbf{elif}\;\varepsilon \leq 1.65 \cdot 10^{-7}:\\ \;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\ \mathbf{else}:\\ \;\;\;\;\cos \varepsilon - \cos x\\ \end{array} \]

Alternative 11: 66.7% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := -1 + \cos \varepsilon\\ \mathbf{if}\;\varepsilon \leq -1.18 \cdot 10^{-5}:\\ \;\;\;\;t_0\\ \mathbf{elif}\;\varepsilon \leq -1.15 \cdot 10^{-58}:\\ \;\;\;\;-0.5 \cdot {\varepsilon}^{2}\\ \mathbf{elif}\;\varepsilon \leq 2.9 \cdot 10^{-7}:\\ \;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\ \mathbf{else}:\\ \;\;\;\;t_0\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (+ -1.0 (cos eps))))
   (if (<= eps -1.18e-5)
     t_0
     (if (<= eps -1.15e-58)
       (* -0.5 (pow eps 2.0))
       (if (<= eps 2.9e-7) (* eps (- (sin x))) t_0)))))
double code(double x, double eps) {
	double t_0 = -1.0 + cos(eps);
	double tmp;
	if (eps <= -1.18e-5) {
		tmp = t_0;
	} else if (eps <= -1.15e-58) {
		tmp = -0.5 * pow(eps, 2.0);
	} else if (eps <= 2.9e-7) {
		tmp = eps * -sin(x);
	} else {
		tmp = t_0;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: t_0
    real(8) :: tmp
    t_0 = (-1.0d0) + cos(eps)
    if (eps <= (-1.18d-5)) then
        tmp = t_0
    else if (eps <= (-1.15d-58)) then
        tmp = (-0.5d0) * (eps ** 2.0d0)
    else if (eps <= 2.9d-7) then
        tmp = eps * -sin(x)
    else
        tmp = t_0
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double t_0 = -1.0 + Math.cos(eps);
	double tmp;
	if (eps <= -1.18e-5) {
		tmp = t_0;
	} else if (eps <= -1.15e-58) {
		tmp = -0.5 * Math.pow(eps, 2.0);
	} else if (eps <= 2.9e-7) {
		tmp = eps * -Math.sin(x);
	} else {
		tmp = t_0;
	}
	return tmp;
}
def code(x, eps):
	t_0 = -1.0 + math.cos(eps)
	tmp = 0
	if eps <= -1.18e-5:
		tmp = t_0
	elif eps <= -1.15e-58:
		tmp = -0.5 * math.pow(eps, 2.0)
	elif eps <= 2.9e-7:
		tmp = eps * -math.sin(x)
	else:
		tmp = t_0
	return tmp
function code(x, eps)
	t_0 = Float64(-1.0 + cos(eps))
	tmp = 0.0
	if (eps <= -1.18e-5)
		tmp = t_0;
	elseif (eps <= -1.15e-58)
		tmp = Float64(-0.5 * (eps ^ 2.0));
	elseif (eps <= 2.9e-7)
		tmp = Float64(eps * Float64(-sin(x)));
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(x, eps)
	t_0 = -1.0 + cos(eps);
	tmp = 0.0;
	if (eps <= -1.18e-5)
		tmp = t_0;
	elseif (eps <= -1.15e-58)
		tmp = -0.5 * (eps ^ 2.0);
	elseif (eps <= 2.9e-7)
		tmp = eps * -sin(x);
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := Block[{t$95$0 = N[(-1.0 + N[Cos[eps], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[eps, -1.18e-5], t$95$0, If[LessEqual[eps, -1.15e-58], N[(-0.5 * N[Power[eps, 2.0], $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 2.9e-7], N[(eps * (-N[Sin[x], $MachinePrecision])), $MachinePrecision], t$95$0]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := -1 + \cos \varepsilon\\
\mathbf{if}\;\varepsilon \leq -1.18 \cdot 10^{-5}:\\
\;\;\;\;t_0\\

\mathbf{elif}\;\varepsilon \leq -1.15 \cdot 10^{-58}:\\
\;\;\;\;-0.5 \cdot {\varepsilon}^{2}\\

\mathbf{elif}\;\varepsilon \leq 2.9 \cdot 10^{-7}:\\
\;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\

\mathbf{else}:\\
\;\;\;\;t_0\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -1.18000000000000005e-5 or 2.8999999999999998e-7 < eps

    1. Initial program 50.9%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 52.8%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]

    if -1.18000000000000005e-5 < eps < -1.1499999999999999e-58

    1. Initial program 7.1%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 7.1%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
    3. Taylor expanded in eps around 0 79.9%

      \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]

    if -1.1499999999999999e-58 < eps < 2.8999999999999998e-7

    1. Initial program 22.8%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in eps around 0 86.8%

      \[\leadsto \color{blue}{-1 \cdot \left(\varepsilon \cdot \sin x\right)} \]
    3. Step-by-step derivation
      1. mul-1-neg86.8%

        \[\leadsto \color{blue}{-\varepsilon \cdot \sin x} \]
      2. *-commutative86.8%

        \[\leadsto -\color{blue}{\sin x \cdot \varepsilon} \]
      3. distribute-rgt-neg-in86.8%

        \[\leadsto \color{blue}{\sin x \cdot \left(-\varepsilon\right)} \]
    4. Simplified86.8%

      \[\leadsto \color{blue}{\sin x \cdot \left(-\varepsilon\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification68.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -1.18 \cdot 10^{-5}:\\ \;\;\;\;-1 + \cos \varepsilon\\ \mathbf{elif}\;\varepsilon \leq -1.15 \cdot 10^{-58}:\\ \;\;\;\;-0.5 \cdot {\varepsilon}^{2}\\ \mathbf{elif}\;\varepsilon \leq 2.9 \cdot 10^{-7}:\\ \;\;\;\;\varepsilon \cdot \left(-\sin x\right)\\ \mathbf{else}:\\ \;\;\;\;-1 + \cos \varepsilon\\ \end{array} \]

Alternative 12: 46.0% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -1.18 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 0.00015\right):\\ \;\;\;\;-1 + \cos \varepsilon\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot {\varepsilon}^{2}\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -1.18e-5) (not (<= eps 0.00015)))
   (+ -1.0 (cos eps))
   (* -0.5 (pow eps 2.0))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -1.18e-5) || !(eps <= 0.00015)) {
		tmp = -1.0 + cos(eps);
	} else {
		tmp = -0.5 * pow(eps, 2.0);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-1.18d-5)) .or. (.not. (eps <= 0.00015d0))) then
        tmp = (-1.0d0) + cos(eps)
    else
        tmp = (-0.5d0) * (eps ** 2.0d0)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -1.18e-5) || !(eps <= 0.00015)) {
		tmp = -1.0 + Math.cos(eps);
	} else {
		tmp = -0.5 * Math.pow(eps, 2.0);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -1.18e-5) or not (eps <= 0.00015):
		tmp = -1.0 + math.cos(eps)
	else:
		tmp = -0.5 * math.pow(eps, 2.0)
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -1.18e-5) || !(eps <= 0.00015))
		tmp = Float64(-1.0 + cos(eps));
	else
		tmp = Float64(-0.5 * (eps ^ 2.0));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -1.18e-5) || ~((eps <= 0.00015)))
		tmp = -1.0 + cos(eps);
	else
		tmp = -0.5 * (eps ^ 2.0);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -1.18e-5], N[Not[LessEqual[eps, 0.00015]], $MachinePrecision]], N[(-1.0 + N[Cos[eps], $MachinePrecision]), $MachinePrecision], N[(-0.5 * N[Power[eps, 2.0], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -1.18 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 0.00015\right):\\
\;\;\;\;-1 + \cos \varepsilon\\

\mathbf{else}:\\
\;\;\;\;-0.5 \cdot {\varepsilon}^{2}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -1.18000000000000005e-5 or 1.49999999999999987e-4 < eps

    1. Initial program 51.0%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 53.0%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]

    if -1.18000000000000005e-5 < eps < 1.49999999999999987e-4

    1. Initial program 21.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 21.6%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
    3. Taylor expanded in eps around 0 40.9%

      \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification47.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -1.18 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 0.00015\right):\\ \;\;\;\;-1 + \cos \varepsilon\\ \mathbf{else}:\\ \;\;\;\;-0.5 \cdot {\varepsilon}^{2}\\ \end{array} \]

Alternative 13: 27.9% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -1.9 \lor \neg \left(\varepsilon \leq 1.65\right):\\ \;\;\;\;-1 - \cos x\\ \mathbf{else}:\\ \;\;\;\;\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -1.9) (not (<= eps 1.65)))
   (- -1.0 (cos x))
   (* (* eps eps) -0.5)))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -1.9) || !(eps <= 1.65)) {
		tmp = -1.0 - cos(x);
	} else {
		tmp = (eps * eps) * -0.5;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-1.9d0)) .or. (.not. (eps <= 1.65d0))) then
        tmp = (-1.0d0) - cos(x)
    else
        tmp = (eps * eps) * (-0.5d0)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -1.9) || !(eps <= 1.65)) {
		tmp = -1.0 - Math.cos(x);
	} else {
		tmp = (eps * eps) * -0.5;
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -1.9) or not (eps <= 1.65):
		tmp = -1.0 - math.cos(x)
	else:
		tmp = (eps * eps) * -0.5
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -1.9) || !(eps <= 1.65))
		tmp = Float64(-1.0 - cos(x));
	else
		tmp = Float64(Float64(eps * eps) * -0.5);
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -1.9) || ~((eps <= 1.65)))
		tmp = -1.0 - cos(x);
	else
		tmp = (eps * eps) * -0.5;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -1.9], N[Not[LessEqual[eps, 1.65]], $MachinePrecision]], N[(-1.0 - N[Cos[x], $MachinePrecision]), $MachinePrecision], N[(N[(eps * eps), $MachinePrecision] * -0.5), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -1.9 \lor \neg \left(\varepsilon \leq 1.65\right):\\
\;\;\;\;-1 - \cos x\\

\mathbf{else}:\\
\;\;\;\;\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -1.8999999999999999 or 1.6499999999999999 < eps

    1. Initial program 51.8%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Step-by-step derivation
      1. add-cube-cbrt51.8%

        \[\leadsto \color{blue}{\left(\sqrt[3]{\cos \left(x + \varepsilon\right)} \cdot \sqrt[3]{\cos \left(x + \varepsilon\right)}\right) \cdot \sqrt[3]{\cos \left(x + \varepsilon\right)}} - \cos x \]
      2. pow351.8%

        \[\leadsto \color{blue}{{\left(\sqrt[3]{\cos \left(x + \varepsilon\right)}\right)}^{3}} - \cos x \]
    3. Applied egg-rr51.8%

      \[\leadsto \color{blue}{{\left(\sqrt[3]{\cos \left(x + \varepsilon\right)}\right)}^{3}} - \cos x \]
    4. Taylor expanded in x around 0 25.5%

      \[\leadsto {\color{blue}{\left({\cos \varepsilon}^{0.3333333333333333}\right)}}^{3} - \cos x \]
    5. Step-by-step derivation
      1. unpow1/354.6%

        \[\leadsto {\color{blue}{\left(\sqrt[3]{\cos \varepsilon}\right)}}^{3} - \cos x \]
    6. Simplified54.6%

      \[\leadsto {\color{blue}{\left(\sqrt[3]{\cos \varepsilon}\right)}}^{3} - \cos x \]
    7. Taylor expanded in eps around 0 6.7%

      \[\leadsto \color{blue}{1} - \cos x \]
    8. Simplified15.9%

      \[\leadsto \color{blue}{-1} - \cos x \]

    if -1.8999999999999999 < eps < 1.6499999999999999

    1. Initial program 21.3%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 21.4%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
    3. Taylor expanded in eps around 0 40.4%

      \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
    4. Step-by-step derivation
      1. unpow299.4%

        \[\leadsto \left(\left(-0.125 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    5. Applied egg-rr40.4%

      \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification28.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -1.9 \lor \neg \left(\varepsilon \leq 1.65\right):\\ \;\;\;\;-1 - \cos x\\ \mathbf{else}:\\ \;\;\;\;\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5\\ \end{array} \]

Alternative 14: 46.0% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -1.18 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 0.00015\right):\\ \;\;\;\;-1 + \cos \varepsilon\\ \mathbf{else}:\\ \;\;\;\;\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -1.18e-5) (not (<= eps 0.00015)))
   (+ -1.0 (cos eps))
   (* (* eps eps) -0.5)))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -1.18e-5) || !(eps <= 0.00015)) {
		tmp = -1.0 + cos(eps);
	} else {
		tmp = (eps * eps) * -0.5;
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-1.18d-5)) .or. (.not. (eps <= 0.00015d0))) then
        tmp = (-1.0d0) + cos(eps)
    else
        tmp = (eps * eps) * (-0.5d0)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -1.18e-5) || !(eps <= 0.00015)) {
		tmp = -1.0 + Math.cos(eps);
	} else {
		tmp = (eps * eps) * -0.5;
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -1.18e-5) or not (eps <= 0.00015):
		tmp = -1.0 + math.cos(eps)
	else:
		tmp = (eps * eps) * -0.5
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -1.18e-5) || !(eps <= 0.00015))
		tmp = Float64(-1.0 + cos(eps));
	else
		tmp = Float64(Float64(eps * eps) * -0.5);
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -1.18e-5) || ~((eps <= 0.00015)))
		tmp = -1.0 + cos(eps);
	else
		tmp = (eps * eps) * -0.5;
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -1.18e-5], N[Not[LessEqual[eps, 0.00015]], $MachinePrecision]], N[(-1.0 + N[Cos[eps], $MachinePrecision]), $MachinePrecision], N[(N[(eps * eps), $MachinePrecision] * -0.5), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -1.18 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 0.00015\right):\\
\;\;\;\;-1 + \cos \varepsilon\\

\mathbf{else}:\\
\;\;\;\;\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -1.18000000000000005e-5 or 1.49999999999999987e-4 < eps

    1. Initial program 51.0%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 53.0%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]

    if -1.18000000000000005e-5 < eps < 1.49999999999999987e-4

    1. Initial program 21.6%

      \[\cos \left(x + \varepsilon\right) - \cos x \]
    2. Taylor expanded in x around 0 21.6%

      \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
    3. Taylor expanded in eps around 0 40.9%

      \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
    4. Step-by-step derivation
      1. unpow299.8%

        \[\leadsto \left(\left(-0.125 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
    5. Applied egg-rr40.9%

      \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification47.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -1.18 \cdot 10^{-5} \lor \neg \left(\varepsilon \leq 0.00015\right):\\ \;\;\;\;-1 + \cos \varepsilon\\ \mathbf{else}:\\ \;\;\;\;\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5\\ \end{array} \]

Alternative 15: 22.1% accurate, 41.0× speedup?

\[\begin{array}{l} \\ \left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 \end{array} \]
(FPCore (x eps) :precision binary64 (* (* eps eps) -0.5))
double code(double x, double eps) {
	return (eps * eps) * -0.5;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = (eps * eps) * (-0.5d0)
end function
public static double code(double x, double eps) {
	return (eps * eps) * -0.5;
}
def code(x, eps):
	return (eps * eps) * -0.5
function code(x, eps)
	return Float64(Float64(eps * eps) * -0.5)
end
function tmp = code(x, eps)
	tmp = (eps * eps) * -0.5;
end
code[x_, eps_] := N[(N[(eps * eps), $MachinePrecision] * -0.5), $MachinePrecision]
\begin{array}{l}

\\
\left(\varepsilon \cdot \varepsilon\right) \cdot -0.5
\end{array}
Derivation
  1. Initial program 36.8%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Taylor expanded in x around 0 37.8%

    \[\leadsto \color{blue}{\cos \varepsilon - 1} \]
  3. Taylor expanded in eps around 0 21.6%

    \[\leadsto \color{blue}{-0.5 \cdot {\varepsilon}^{2}} \]
  4. Step-by-step derivation
    1. unpow249.9%

      \[\leadsto \left(\left(-0.125 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} + 1\right) \cdot \sin x + \cos x \cdot \left(0.5 \cdot \varepsilon + -0.020833333333333332 \cdot {\varepsilon}^{3}\right)\right) \cdot \left(-2 \cdot \sin \left(\varepsilon \cdot 0.5\right)\right) \]
  5. Applied egg-rr21.6%

    \[\leadsto -0.5 \cdot \color{blue}{\left(\varepsilon \cdot \varepsilon\right)} \]
  6. Final simplification21.6%

    \[\leadsto \left(\varepsilon \cdot \varepsilon\right) \cdot -0.5 \]

Alternative 16: 13.4% accurate, 205.0× speedup?

\[\begin{array}{l} \\ 0 \end{array} \]
(FPCore (x eps) :precision binary64 0.0)
double code(double x, double eps) {
	return 0.0;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = 0.0d0
end function
public static double code(double x, double eps) {
	return 0.0;
}
def code(x, eps):
	return 0.0
function code(x, eps)
	return 0.0
end
function tmp = code(x, eps)
	tmp = 0.0;
end
code[x_, eps_] := 0.0
\begin{array}{l}

\\
0
\end{array}
Derivation
  1. Initial program 36.8%

    \[\cos \left(x + \varepsilon\right) - \cos x \]
  2. Step-by-step derivation
    1. add-cube-cbrt36.5%

      \[\leadsto \color{blue}{\left(\sqrt[3]{\cos \left(x + \varepsilon\right)} \cdot \sqrt[3]{\cos \left(x + \varepsilon\right)}\right) \cdot \sqrt[3]{\cos \left(x + \varepsilon\right)}} - \cos x \]
    2. pow336.6%

      \[\leadsto \color{blue}{{\left(\sqrt[3]{\cos \left(x + \varepsilon\right)}\right)}^{3}} - \cos x \]
  3. Applied egg-rr36.6%

    \[\leadsto \color{blue}{{\left(\sqrt[3]{\cos \left(x + \varepsilon\right)}\right)}^{3}} - \cos x \]
  4. Taylor expanded in eps around 0 11.6%

    \[\leadsto \color{blue}{{1}^{0.3333333333333333} \cdot \cos x - \cos x} \]
  5. Step-by-step derivation
    1. pow-base-111.6%

      \[\leadsto \color{blue}{1} \cdot \cos x - \cos x \]
    2. *-lft-identity11.6%

      \[\leadsto \color{blue}{\cos x} - \cos x \]
    3. +-inverses11.6%

      \[\leadsto \color{blue}{0} \]
  6. Simplified11.6%

    \[\leadsto \color{blue}{0} \]
  7. Final simplification11.6%

    \[\leadsto 0 \]

Reproduce

?
herbie shell --seed 2023311 
(FPCore (x eps)
  :name "2cos (problem 3.3.5)"
  :precision binary64
  (- (cos (+ x eps)) (cos x)))