2sin (example 3.3)

Percentage Accurate: 42.6% → 99.7%
Time: 15.9s
Alternatives: 8
Speedup: 2.0×

Specification

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

\\
\sin \left(x + \varepsilon\right) - \sin 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 8 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: 42.6% accurate, 1.0× speedup?

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

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

Alternative 1: 99.7% accurate, 0.4× speedup?

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

\\
\cos x \cdot \sin \varepsilon - \tan \left(\frac{\varepsilon}{2}\right) \cdot \left(\sin \varepsilon \cdot \sin x\right)
\end{array}
Derivation
  1. Initial program 45.1%

    \[\sin \left(x + \varepsilon\right) - \sin x \]
  2. Step-by-step derivation
    1. sin-sum67.3%

      \[\leadsto \color{blue}{\left(\sin x \cdot \cos \varepsilon + \cos x \cdot \sin \varepsilon\right)} - \sin x \]
    2. associate--l+67.3%

      \[\leadsto \color{blue}{\sin x \cdot \cos \varepsilon + \left(\cos x \cdot \sin \varepsilon - \sin x\right)} \]
  3. Applied egg-rr67.3%

    \[\leadsto \color{blue}{\sin x \cdot \cos \varepsilon + \left(\cos x \cdot \sin \varepsilon - \sin x\right)} \]
  4. Taylor expanded in x around inf 67.3%

    \[\leadsto \color{blue}{\left(\cos \varepsilon \cdot \sin x + \cos x \cdot \sin \varepsilon\right) - \sin x} \]
  5. Step-by-step derivation
    1. associate--l+67.3%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \sin x + \left(\cos x \cdot \sin \varepsilon - \sin x\right)} \]
    2. *-commutative67.3%

      \[\leadsto \color{blue}{\sin x \cdot \cos \varepsilon} + \left(\cos x \cdot \sin \varepsilon - \sin x\right) \]
    3. +-commutative67.3%

      \[\leadsto \color{blue}{\left(\cos x \cdot \sin \varepsilon - \sin x\right) + \sin x \cdot \cos \varepsilon} \]
    4. associate-+l-99.5%

      \[\leadsto \color{blue}{\cos x \cdot \sin \varepsilon - \left(\sin x - \sin x \cdot \cos \varepsilon\right)} \]
    5. *-rgt-identity99.5%

      \[\leadsto \cos x \cdot \sin \varepsilon - \left(\color{blue}{\sin x \cdot 1} - \sin x \cdot \cos \varepsilon\right) \]
    6. distribute-lft-out--99.5%

      \[\leadsto \cos x \cdot \sin \varepsilon - \color{blue}{\sin x \cdot \left(1 - \cos \varepsilon\right)} \]
  6. Simplified99.5%

    \[\leadsto \color{blue}{\cos x \cdot \sin \varepsilon - \sin x \cdot \left(1 - \cos \varepsilon\right)} \]
  7. Step-by-step derivation
    1. flip--99.3%

      \[\leadsto \cos x \cdot \sin \varepsilon - \sin x \cdot \color{blue}{\frac{1 \cdot 1 - \cos \varepsilon \cdot \cos \varepsilon}{1 + \cos \varepsilon}} \]
    2. associate-*r/99.4%

      \[\leadsto \cos x \cdot \sin \varepsilon - \color{blue}{\frac{\sin x \cdot \left(1 \cdot 1 - \cos \varepsilon \cdot \cos \varepsilon\right)}{1 + \cos \varepsilon}} \]
    3. metadata-eval99.4%

      \[\leadsto \cos x \cdot \sin \varepsilon - \frac{\sin x \cdot \left(\color{blue}{1} - \cos \varepsilon \cdot \cos \varepsilon\right)}{1 + \cos \varepsilon} \]
    4. 1-sub-cos99.6%

      \[\leadsto \cos x \cdot \sin \varepsilon - \frac{\sin x \cdot \color{blue}{\left(\sin \varepsilon \cdot \sin \varepsilon\right)}}{1 + \cos \varepsilon} \]
    5. pow299.6%

      \[\leadsto \cos x \cdot \sin \varepsilon - \frac{\sin x \cdot \color{blue}{{\sin \varepsilon}^{2}}}{1 + \cos \varepsilon} \]
  8. Applied egg-rr99.6%

    \[\leadsto \cos x \cdot \sin \varepsilon - \color{blue}{\frac{\sin x \cdot {\sin \varepsilon}^{2}}{1 + \cos \varepsilon}} \]
  9. Step-by-step derivation
    1. *-commutative99.6%

      \[\leadsto \cos x \cdot \sin \varepsilon - \frac{\color{blue}{{\sin \varepsilon}^{2} \cdot \sin x}}{1 + \cos \varepsilon} \]
    2. associate-/l*99.6%

      \[\leadsto \cos x \cdot \sin \varepsilon - \color{blue}{\frac{{\sin \varepsilon}^{2}}{\frac{1 + \cos \varepsilon}{\sin x}}} \]
  10. Simplified99.6%

    \[\leadsto \cos x \cdot \sin \varepsilon - \color{blue}{\frac{{\sin \varepsilon}^{2}}{\frac{1 + \cos \varepsilon}{\sin x}}} \]
  11. Taylor expanded in eps around inf 99.6%

    \[\leadsto \cos x \cdot \sin \varepsilon - \color{blue}{\frac{{\sin \varepsilon}^{2} \cdot \sin x}{1 + \cos \varepsilon}} \]
  12. Step-by-step derivation
    1. unpow299.6%

      \[\leadsto \cos x \cdot \sin \varepsilon - \frac{\color{blue}{\left(\sin \varepsilon \cdot \sin \varepsilon\right)} \cdot \sin x}{1 + \cos \varepsilon} \]
    2. associate-*r*99.6%

      \[\leadsto \cos x \cdot \sin \varepsilon - \frac{\color{blue}{\sin \varepsilon \cdot \left(\sin \varepsilon \cdot \sin x\right)}}{1 + \cos \varepsilon} \]
    3. /-rgt-identity99.6%

      \[\leadsto \cos x \cdot \sin \varepsilon - \frac{\sin \varepsilon \cdot \left(\color{blue}{\frac{\sin \varepsilon}{1}} \cdot \sin x\right)}{1 + \cos \varepsilon} \]
    4. associate-/r/99.6%

      \[\leadsto \cos x \cdot \sin \varepsilon - \frac{\sin \varepsilon \cdot \color{blue}{\frac{\sin \varepsilon}{\frac{1}{\sin x}}}}{1 + \cos \varepsilon} \]
    5. associate-*l/99.6%

      \[\leadsto \cos x \cdot \sin \varepsilon - \color{blue}{\frac{\sin \varepsilon}{1 + \cos \varepsilon} \cdot \frac{\sin \varepsilon}{\frac{1}{\sin x}}} \]
    6. associate-/r/99.6%

      \[\leadsto \cos x \cdot \sin \varepsilon - \frac{\sin \varepsilon}{1 + \cos \varepsilon} \cdot \color{blue}{\left(\frac{\sin \varepsilon}{1} \cdot \sin x\right)} \]
    7. /-rgt-identity99.6%

      \[\leadsto \cos x \cdot \sin \varepsilon - \frac{\sin \varepsilon}{1 + \cos \varepsilon} \cdot \left(\color{blue}{\sin \varepsilon} \cdot \sin x\right) \]
    8. hang-0p-tan99.8%

      \[\leadsto \cos x \cdot \sin \varepsilon - \color{blue}{\tan \left(\frac{\varepsilon}{2}\right)} \cdot \left(\sin \varepsilon \cdot \sin x\right) \]
  13. Simplified99.8%

    \[\leadsto \cos x \cdot \sin \varepsilon - \color{blue}{\tan \left(\frac{\varepsilon}{2}\right) \cdot \left(\sin \varepsilon \cdot \sin x\right)} \]
  14. Final simplification99.8%

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

Alternative 2: 76.6% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \sin \left(x + \varepsilon\right) - \sin x\\ \mathbf{if}\;t_0 \leq -0.1 \lor \neg \left(t_0 \leq 0.04\right):\\ \;\;\;\;t_0\\ \mathbf{else}:\\ \;\;\;\;\sin \left(\varepsilon \cdot 0.5\right) \cdot \left(\cos x \cdot 2\right)\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (- (sin (+ x eps)) (sin x))))
   (if (or (<= t_0 -0.1) (not (<= t_0 0.04)))
     t_0
     (* (sin (* eps 0.5)) (* (cos x) 2.0)))))
double code(double x, double eps) {
	double t_0 = sin((x + eps)) - sin(x);
	double tmp;
	if ((t_0 <= -0.1) || !(t_0 <= 0.04)) {
		tmp = t_0;
	} else {
		tmp = sin((eps * 0.5)) * (cos(x) * 2.0);
	}
	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 = sin((x + eps)) - sin(x)
    if ((t_0 <= (-0.1d0)) .or. (.not. (t_0 <= 0.04d0))) then
        tmp = t_0
    else
        tmp = sin((eps * 0.5d0)) * (cos(x) * 2.0d0)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double t_0 = Math.sin((x + eps)) - Math.sin(x);
	double tmp;
	if ((t_0 <= -0.1) || !(t_0 <= 0.04)) {
		tmp = t_0;
	} else {
		tmp = Math.sin((eps * 0.5)) * (Math.cos(x) * 2.0);
	}
	return tmp;
}
def code(x, eps):
	t_0 = math.sin((x + eps)) - math.sin(x)
	tmp = 0
	if (t_0 <= -0.1) or not (t_0 <= 0.04):
		tmp = t_0
	else:
		tmp = math.sin((eps * 0.5)) * (math.cos(x) * 2.0)
	return tmp
function code(x, eps)
	t_0 = Float64(sin(Float64(x + eps)) - sin(x))
	tmp = 0.0
	if ((t_0 <= -0.1) || !(t_0 <= 0.04))
		tmp = t_0;
	else
		tmp = Float64(sin(Float64(eps * 0.5)) * Float64(cos(x) * 2.0));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	t_0 = sin((x + eps)) - sin(x);
	tmp = 0.0;
	if ((t_0 <= -0.1) || ~((t_0 <= 0.04)))
		tmp = t_0;
	else
		tmp = sin((eps * 0.5)) * (cos(x) * 2.0);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := Block[{t$95$0 = N[(N[Sin[N[(x + eps), $MachinePrecision]], $MachinePrecision] - N[Sin[x], $MachinePrecision]), $MachinePrecision]}, If[Or[LessEqual[t$95$0, -0.1], N[Not[LessEqual[t$95$0, 0.04]], $MachinePrecision]], t$95$0, N[(N[Sin[N[(eps * 0.5), $MachinePrecision]], $MachinePrecision] * N[(N[Cos[x], $MachinePrecision] * 2.0), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \sin \left(x + \varepsilon\right) - \sin x\\
\mathbf{if}\;t_0 \leq -0.1 \lor \neg \left(t_0 \leq 0.04\right):\\
\;\;\;\;t_0\\

\mathbf{else}:\\
\;\;\;\;\sin \left(\varepsilon \cdot 0.5\right) \cdot \left(\cos x \cdot 2\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (sin.f64 (+.f64 x eps)) (sin.f64 x)) < -0.10000000000000001 or 0.0400000000000000008 < (-.f64 (sin.f64 (+.f64 x eps)) (sin.f64 x))

    1. Initial program 81.2%

      \[\sin \left(x + \varepsilon\right) - \sin x \]

    if -0.10000000000000001 < (-.f64 (sin.f64 (+.f64 x eps)) (sin.f64 x)) < 0.0400000000000000008

    1. Initial program 24.6%

      \[\sin \left(x + \varepsilon\right) - \sin x \]
    2. Step-by-step derivation
      1. diff-sin24.4%

        \[\leadsto \color{blue}{2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \cos \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
      2. div-inv24.4%

        \[\leadsto 2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \cos \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      3. metadata-eval24.4%

        \[\leadsto 2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \cos \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
      4. div-inv24.4%

        \[\leadsto 2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \cos \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
      5. +-commutative24.4%

        \[\leadsto 2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \cos \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
      6. metadata-eval24.4%

        \[\leadsto 2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
    3. Applied egg-rr24.4%

      \[\leadsto \color{blue}{2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
    4. Step-by-step derivation
      1. associate-*r*24.4%

        \[\leadsto \color{blue}{\left(2 \cdot \sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right)\right) \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)} \]
      2. *-commutative24.4%

        \[\leadsto \color{blue}{\left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot 2\right)} \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right) \]
      3. associate-*l*24.4%

        \[\leadsto \color{blue}{\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
      4. +-commutative24.4%

        \[\leadsto \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} - x\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      5. associate--l+76.7%

        \[\leadsto \sin \left(\color{blue}{\left(\varepsilon + \left(x - x\right)\right)} \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      6. +-inverses76.7%

        \[\leadsto \sin \left(\left(\varepsilon + \color{blue}{0}\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
      7. *-commutative76.7%

        \[\leadsto \sin \left(\left(\varepsilon + 0\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
      8. associate-+r+76.7%

        \[\leadsto \sin \left(\left(\varepsilon + 0\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right)\right) \]
      9. +-commutative76.7%

        \[\leadsto \sin \left(\left(\varepsilon + 0\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x + x\right)\right)}\right)\right) \]
    5. Simplified76.7%

      \[\leadsto \color{blue}{\sin \left(\left(\varepsilon + 0\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)\right)} \]
    6. Taylor expanded in eps around 0 77.3%

      \[\leadsto \sin \left(\left(\varepsilon + 0\right) \cdot 0.5\right) \cdot \left(2 \cdot \color{blue}{\cos x}\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification78.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\sin \left(x + \varepsilon\right) - \sin x \leq -0.1 \lor \neg \left(\sin \left(x + \varepsilon\right) - \sin x \leq 0.04\right):\\ \;\;\;\;\sin \left(x + \varepsilon\right) - \sin x\\ \mathbf{else}:\\ \;\;\;\;\sin \left(\varepsilon \cdot 0.5\right) \cdot \left(\cos x \cdot 2\right)\\ \end{array} \]

Alternative 3: 99.4% accurate, 0.4× speedup?

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

\\
\cos x \cdot \sin \varepsilon + \left(\sin x \cdot \cos \varepsilon - \sin x\right)
\end{array}
Derivation
  1. Initial program 45.1%

    \[\sin \left(x + \varepsilon\right) - \sin x \]
  2. Step-by-step derivation
    1. sin-sum67.3%

      \[\leadsto \color{blue}{\left(\sin x \cdot \cos \varepsilon + \cos x \cdot \sin \varepsilon\right)} - \sin x \]
    2. associate--l+67.3%

      \[\leadsto \color{blue}{\sin x \cdot \cos \varepsilon + \left(\cos x \cdot \sin \varepsilon - \sin x\right)} \]
  3. Applied egg-rr67.3%

    \[\leadsto \color{blue}{\sin x \cdot \cos \varepsilon + \left(\cos x \cdot \sin \varepsilon - \sin x\right)} \]
  4. Taylor expanded in x around inf 67.3%

    \[\leadsto \color{blue}{\left(\cos \varepsilon \cdot \sin x + \cos x \cdot \sin \varepsilon\right) - \sin x} \]
  5. Step-by-step derivation
    1. associate--l+67.3%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \sin x + \left(\cos x \cdot \sin \varepsilon - \sin x\right)} \]
    2. *-commutative67.3%

      \[\leadsto \color{blue}{\sin x \cdot \cos \varepsilon} + \left(\cos x \cdot \sin \varepsilon - \sin x\right) \]
    3. +-commutative67.3%

      \[\leadsto \color{blue}{\left(\cos x \cdot \sin \varepsilon - \sin x\right) + \sin x \cdot \cos \varepsilon} \]
    4. associate-+l-99.5%

      \[\leadsto \color{blue}{\cos x \cdot \sin \varepsilon - \left(\sin x - \sin x \cdot \cos \varepsilon\right)} \]
    5. *-rgt-identity99.5%

      \[\leadsto \cos x \cdot \sin \varepsilon - \left(\color{blue}{\sin x \cdot 1} - \sin x \cdot \cos \varepsilon\right) \]
    6. distribute-lft-out--99.5%

      \[\leadsto \cos x \cdot \sin \varepsilon - \color{blue}{\sin x \cdot \left(1 - \cos \varepsilon\right)} \]
  6. Simplified99.5%

    \[\leadsto \color{blue}{\cos x \cdot \sin \varepsilon - \sin x \cdot \left(1 - \cos \varepsilon\right)} \]
  7. Step-by-step derivation
    1. sub-neg99.5%

      \[\leadsto \cos x \cdot \sin \varepsilon - \sin x \cdot \color{blue}{\left(1 + \left(-\cos \varepsilon\right)\right)} \]
    2. distribute-lft-in99.5%

      \[\leadsto \cos x \cdot \sin \varepsilon - \color{blue}{\left(\sin x \cdot 1 + \sin x \cdot \left(-\cos \varepsilon\right)\right)} \]
    3. *-commutative99.5%

      \[\leadsto \cos x \cdot \sin \varepsilon - \left(\color{blue}{1 \cdot \sin x} + \sin x \cdot \left(-\cos \varepsilon\right)\right) \]
    4. *-un-lft-identity99.5%

      \[\leadsto \cos x \cdot \sin \varepsilon - \left(\color{blue}{\sin x} + \sin x \cdot \left(-\cos \varepsilon\right)\right) \]
  8. Applied egg-rr99.5%

    \[\leadsto \cos x \cdot \sin \varepsilon - \color{blue}{\left(\sin x + \sin x \cdot \left(-\cos \varepsilon\right)\right)} \]
  9. Final simplification99.5%

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

Alternative 4: 99.4% accurate, 0.5× speedup?

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

\\
\cos x \cdot \sin \varepsilon - \sin x \cdot \left(1 - \cos \varepsilon\right)
\end{array}
Derivation
  1. Initial program 45.1%

    \[\sin \left(x + \varepsilon\right) - \sin x \]
  2. Step-by-step derivation
    1. sin-sum67.3%

      \[\leadsto \color{blue}{\left(\sin x \cdot \cos \varepsilon + \cos x \cdot \sin \varepsilon\right)} - \sin x \]
    2. associate--l+67.3%

      \[\leadsto \color{blue}{\sin x \cdot \cos \varepsilon + \left(\cos x \cdot \sin \varepsilon - \sin x\right)} \]
  3. Applied egg-rr67.3%

    \[\leadsto \color{blue}{\sin x \cdot \cos \varepsilon + \left(\cos x \cdot \sin \varepsilon - \sin x\right)} \]
  4. Taylor expanded in x around inf 67.3%

    \[\leadsto \color{blue}{\left(\cos \varepsilon \cdot \sin x + \cos x \cdot \sin \varepsilon\right) - \sin x} \]
  5. Step-by-step derivation
    1. associate--l+67.3%

      \[\leadsto \color{blue}{\cos \varepsilon \cdot \sin x + \left(\cos x \cdot \sin \varepsilon - \sin x\right)} \]
    2. *-commutative67.3%

      \[\leadsto \color{blue}{\sin x \cdot \cos \varepsilon} + \left(\cos x \cdot \sin \varepsilon - \sin x\right) \]
    3. +-commutative67.3%

      \[\leadsto \color{blue}{\left(\cos x \cdot \sin \varepsilon - \sin x\right) + \sin x \cdot \cos \varepsilon} \]
    4. associate-+l-99.5%

      \[\leadsto \color{blue}{\cos x \cdot \sin \varepsilon - \left(\sin x - \sin x \cdot \cos \varepsilon\right)} \]
    5. *-rgt-identity99.5%

      \[\leadsto \cos x \cdot \sin \varepsilon - \left(\color{blue}{\sin x \cdot 1} - \sin x \cdot \cos \varepsilon\right) \]
    6. distribute-lft-out--99.5%

      \[\leadsto \cos x \cdot \sin \varepsilon - \color{blue}{\sin x \cdot \left(1 - \cos \varepsilon\right)} \]
  6. Simplified99.5%

    \[\leadsto \color{blue}{\cos x \cdot \sin \varepsilon - \sin x \cdot \left(1 - \cos \varepsilon\right)} \]
  7. Final simplification99.5%

    \[\leadsto \cos x \cdot \sin \varepsilon - \sin x \cdot \left(1 - \cos \varepsilon\right) \]

Alternative 5: 77.2% accurate, 1.0× speedup?

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

\\
\sin \left(\varepsilon \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)\right)
\end{array}
Derivation
  1. Initial program 45.1%

    \[\sin \left(x + \varepsilon\right) - \sin x \]
  2. Step-by-step derivation
    1. diff-sin44.8%

      \[\leadsto \color{blue}{2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \cos \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    2. div-inv44.8%

      \[\leadsto 2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \cos \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    3. metadata-eval44.8%

      \[\leadsto 2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \cos \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    4. div-inv44.8%

      \[\leadsto 2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \cos \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
    5. +-commutative44.8%

      \[\leadsto 2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \cos \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
    6. metadata-eval44.8%

      \[\leadsto 2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
  3. Applied egg-rr44.8%

    \[\leadsto \color{blue}{2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
  4. Step-by-step derivation
    1. associate-*r*44.8%

      \[\leadsto \color{blue}{\left(2 \cdot \sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right)\right) \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)} \]
    2. *-commutative44.8%

      \[\leadsto \color{blue}{\left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot 2\right)} \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right) \]
    3. associate-*l*44.8%

      \[\leadsto \color{blue}{\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
    4. +-commutative44.8%

      \[\leadsto \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} - x\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    5. associate--l+78.1%

      \[\leadsto \sin \left(\color{blue}{\left(\varepsilon + \left(x - x\right)\right)} \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    6. +-inverses78.1%

      \[\leadsto \sin \left(\left(\varepsilon + \color{blue}{0}\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    7. *-commutative78.1%

      \[\leadsto \sin \left(\left(\varepsilon + 0\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
    8. associate-+r+78.0%

      \[\leadsto \sin \left(\left(\varepsilon + 0\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right)\right) \]
    9. +-commutative78.0%

      \[\leadsto \sin \left(\left(\varepsilon + 0\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x + x\right)\right)}\right)\right) \]
  5. Simplified78.0%

    \[\leadsto \color{blue}{\sin \left(\left(\varepsilon + 0\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)\right)} \]
  6. Final simplification78.0%

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

Alternative 6: 77.0% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -7 \cdot 10^{-5}:\\ \;\;\;\;\sin \varepsilon\\ \mathbf{elif}\;\varepsilon \leq 0.038:\\ \;\;\;\;\cos x \cdot \varepsilon\\ \mathbf{else}:\\ \;\;\;\;\sin \varepsilon\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -7e-5) (sin eps) (if (<= eps 0.038) (* (cos x) eps) (sin eps))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -7e-5) {
		tmp = sin(eps);
	} else if (eps <= 0.038) {
		tmp = cos(x) * eps;
	} else {
		tmp = sin(eps);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if (eps <= (-7d-5)) then
        tmp = sin(eps)
    else if (eps <= 0.038d0) then
        tmp = cos(x) * eps
    else
        tmp = sin(eps)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if (eps <= -7e-5) {
		tmp = Math.sin(eps);
	} else if (eps <= 0.038) {
		tmp = Math.cos(x) * eps;
	} else {
		tmp = Math.sin(eps);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if eps <= -7e-5:
		tmp = math.sin(eps)
	elif eps <= 0.038:
		tmp = math.cos(x) * eps
	else:
		tmp = math.sin(eps)
	return tmp
function code(x, eps)
	tmp = 0.0
	if (eps <= -7e-5)
		tmp = sin(eps);
	elseif (eps <= 0.038)
		tmp = Float64(cos(x) * eps);
	else
		tmp = sin(eps);
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if (eps <= -7e-5)
		tmp = sin(eps);
	elseif (eps <= 0.038)
		tmp = cos(x) * eps;
	else
		tmp = sin(eps);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[eps, -7e-5], N[Sin[eps], $MachinePrecision], If[LessEqual[eps, 0.038], N[(N[Cos[x], $MachinePrecision] * eps), $MachinePrecision], N[Sin[eps], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -7 \cdot 10^{-5}:\\
\;\;\;\;\sin \varepsilon\\

\mathbf{elif}\;\varepsilon \leq 0.038:\\
\;\;\;\;\cos x \cdot \varepsilon\\

\mathbf{else}:\\
\;\;\;\;\sin \varepsilon\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -6.9999999999999994e-5 or 0.0379999999999999991 < eps

    1. Initial program 58.4%

      \[\sin \left(x + \varepsilon\right) - \sin x \]
    2. Taylor expanded in x around 0 59.9%

      \[\leadsto \color{blue}{\sin \varepsilon} \]

    if -6.9999999999999994e-5 < eps < 0.0379999999999999991

    1. Initial program 31.0%

      \[\sin \left(x + \varepsilon\right) - \sin x \]
    2. Taylor expanded in eps around 0 98.4%

      \[\leadsto \color{blue}{\varepsilon \cdot \cos x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification78.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -7 \cdot 10^{-5}:\\ \;\;\;\;\sin \varepsilon\\ \mathbf{elif}\;\varepsilon \leq 0.038:\\ \;\;\;\;\cos x \cdot \varepsilon\\ \mathbf{else}:\\ \;\;\;\;\sin \varepsilon\\ \end{array} \]

Alternative 7: 55.1% accurate, 2.0× speedup?

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

\\
\sin \varepsilon
\end{array}
Derivation
  1. Initial program 45.1%

    \[\sin \left(x + \varepsilon\right) - \sin x \]
  2. Taylor expanded in x around 0 60.2%

    \[\leadsto \color{blue}{\sin \varepsilon} \]
  3. Final simplification60.2%

    \[\leadsto \sin \varepsilon \]

Alternative 8: 29.2% accurate, 205.0× speedup?

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

\\
\varepsilon
\end{array}
Derivation
  1. Initial program 45.1%

    \[\sin \left(x + \varepsilon\right) - \sin x \]
  2. Step-by-step derivation
    1. diff-sin44.8%

      \[\leadsto \color{blue}{2 \cdot \left(\sin \left(\frac{\left(x + \varepsilon\right) - x}{2}\right) \cdot \cos \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right)} \]
    2. div-inv44.8%

      \[\leadsto 2 \cdot \left(\sin \color{blue}{\left(\left(\left(x + \varepsilon\right) - x\right) \cdot \frac{1}{2}\right)} \cdot \cos \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    3. metadata-eval44.8%

      \[\leadsto 2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot \color{blue}{0.5}\right) \cdot \cos \left(\frac{\left(x + \varepsilon\right) + x}{2}\right)\right) \]
    4. div-inv44.8%

      \[\leadsto 2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \cos \color{blue}{\left(\left(\left(x + \varepsilon\right) + x\right) \cdot \frac{1}{2}\right)}\right) \]
    5. +-commutative44.8%

      \[\leadsto 2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \cos \left(\color{blue}{\left(x + \left(x + \varepsilon\right)\right)} \cdot \frac{1}{2}\right)\right) \]
    6. metadata-eval44.8%

      \[\leadsto 2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot \color{blue}{0.5}\right)\right) \]
  3. Applied egg-rr44.8%

    \[\leadsto \color{blue}{2 \cdot \left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
  4. Step-by-step derivation
    1. associate-*r*44.8%

      \[\leadsto \color{blue}{\left(2 \cdot \sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right)\right) \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)} \]
    2. *-commutative44.8%

      \[\leadsto \color{blue}{\left(\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot 2\right)} \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right) \]
    3. associate-*l*44.8%

      \[\leadsto \color{blue}{\sin \left(\left(\left(x + \varepsilon\right) - x\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right)} \]
    4. +-commutative44.8%

      \[\leadsto \sin \left(\left(\color{blue}{\left(\varepsilon + x\right)} - x\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    5. associate--l+78.1%

      \[\leadsto \sin \left(\color{blue}{\left(\varepsilon + \left(x - x\right)\right)} \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    6. +-inverses78.1%

      \[\leadsto \sin \left(\left(\varepsilon + \color{blue}{0}\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(\left(x + \left(x + \varepsilon\right)\right) \cdot 0.5\right)\right) \]
    7. *-commutative78.1%

      \[\leadsto \sin \left(\left(\varepsilon + 0\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \color{blue}{\left(0.5 \cdot \left(x + \left(x + \varepsilon\right)\right)\right)}\right) \]
    8. associate-+r+78.0%

      \[\leadsto \sin \left(\left(\varepsilon + 0\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(0.5 \cdot \color{blue}{\left(\left(x + x\right) + \varepsilon\right)}\right)\right) \]
    9. +-commutative78.0%

      \[\leadsto \sin \left(\left(\varepsilon + 0\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(0.5 \cdot \color{blue}{\left(\varepsilon + \left(x + x\right)\right)}\right)\right) \]
  5. Simplified78.0%

    \[\leadsto \color{blue}{\sin \left(\left(\varepsilon + 0\right) \cdot 0.5\right) \cdot \left(2 \cdot \cos \left(0.5 \cdot \left(\varepsilon + \left(x + x\right)\right)\right)\right)} \]
  6. Taylor expanded in eps around 0 49.5%

    \[\leadsto \color{blue}{\varepsilon \cdot \cos x} \]
  7. Step-by-step derivation
    1. *-commutative49.5%

      \[\leadsto \color{blue}{\cos x \cdot \varepsilon} \]
  8. Simplified49.5%

    \[\leadsto \color{blue}{\cos x \cdot \varepsilon} \]
  9. Taylor expanded in x around 0 31.1%

    \[\leadsto \color{blue}{\varepsilon} \]
  10. Final simplification31.1%

    \[\leadsto \varepsilon \]

Developer target: 77.2% accurate, 1.0× speedup?

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

\\
2 \cdot \left(\cos \left(x + \frac{\varepsilon}{2}\right) \cdot \sin \left(\frac{\varepsilon}{2}\right)\right)
\end{array}

Reproduce

?
herbie shell --seed 2023285 
(FPCore (x eps)
  :name "2sin (example 3.3)"
  :precision binary64

  :herbie-target
  (* 2.0 (* (cos (+ x (/ eps 2.0))) (sin (/ eps 2.0))))

  (- (sin (+ x eps)) (sin x)))