Average Error: 0.0 → 0.0
Time: 3.9s
Precision: binary64
Cost: 26176
\[2 \cdot \tan^{-1} \left(\sqrt{\frac{1 - x}{1 + x}}\right) \]
↓
\[2 \cdot \mathsf{log1p}\left(\mathsf{expm1}\left(\tan^{-1} \left(\sqrt{\frac{1 - x}{1 + x}}\right)\right)\right) \]
(FPCore (x) :precision binary64 (* 2.0 (atan (sqrt (/ (- 1.0 x) (+ 1.0 x))))))
↓
(FPCore (x)
 :precision binary64
 (* 2.0 (log1p (expm1 (atan (sqrt (/ (- 1.0 x) (+ 1.0 x))))))))
double code(double x) {
	return 2.0 * atan(sqrt(((1.0 - x) / (1.0 + x))));
}
↓
double code(double x) {
	return 2.0 * log1p(expm1(atan(sqrt(((1.0 - x) / (1.0 + x))))));
}

public static double code(double x) {
	return 2.0 * Math.atan(Math.sqrt(((1.0 - x) / (1.0 + x))));
}
↓
public static double code(double x) {
	return 2.0 * Math.log1p(Math.expm1(Math.atan(Math.sqrt(((1.0 - x) / (1.0 + x))))));
}

def code(x):
	return 2.0 * math.atan(math.sqrt(((1.0 - x) / (1.0 + x))))
↓
def code(x):
	return 2.0 * math.log1p(math.expm1(math.atan(math.sqrt(((1.0 - x) / (1.0 + x))))))

function code(x)
	return Float64(2.0 * atan(sqrt(Float64(Float64(1.0 - x) / Float64(1.0 + x)))))
end
↓
function code(x)
	return Float64(2.0 * log1p(expm1(atan(sqrt(Float64(Float64(1.0 - x) / Float64(1.0 + x)))))))
end

code[x_] := N[(2.0 * N[ArcTan[N[Sqrt[N[(N[(1.0 - x), $MachinePrecision] / N[(1.0 + x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
↓
code[x_] := N[(2.0 * N[Log[1 + N[(Exp[N[ArcTan[N[Sqrt[N[(N[(1.0 - x), $MachinePrecision] / N[(1.0 + x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]] - 1), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]

2 \cdot \tan^{-1} \left(\sqrt{\frac{1 - x}{1 + x}}\right)
↓
2 \cdot \mathsf{log1p}\left(\mathsf{expm1}\left(\tan^{-1} \left(\sqrt{\frac{1 - x}{1 + x}}\right)\right)\right)

Error

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Initial program 0.0

    \[2 \cdot \tan^{-1} \left(\sqrt{\frac{1 - x}{1 + x}}\right) \]

  2. Simplified0.0

    \[\leadsto \color{blue}{2 \cdot \tan^{-1} \left(\sqrt{\frac{1 - x}{x - -1}}\right)} \]
    Proof
    (*.f64 2 (atan.f64 (sqrt.f64 (/.f64 (-.f64 1 x) (-.f64 x -1))))): 0 points increase in error, 0 points decrease in error
    (*.f64 2 (atan.f64 (sqrt.f64 (/.f64 (-.f64 1 x) (Rewrite=> sub-neg_binary64 (+.f64 x (neg.f64 -1))))))): 0 points increase in error, 0 points decrease in error
    (*.f64 2 (atan.f64 (sqrt.f64 (/.f64 (-.f64 1 x) (+.f64 x (Rewrite=> metadata-eval 1)))))): 0 points increase in error, 0 points decrease in error
    (*.f64 2 (atan.f64 (sqrt.f64 (/.f64 (-.f64 1 x) (Rewrite<= +-commutative_binary64 (+.f64 1 x)))))): 0 points increase in error, 0 points decrease in error

  3. Applied egg-rr0.0

    \[\leadsto 2 \cdot \color{blue}{\mathsf{log1p}\left(\mathsf{expm1}\left(\tan^{-1} \left(\sqrt{\frac{1 - x}{1 + x}}\right)\right)\right)} \]

  4. Final simplification0.0

    \[\leadsto 2 \cdot \mathsf{log1p}\left(\mathsf{expm1}\left(\tan^{-1} \left(\sqrt{\frac{1 - x}{1 + x}}\right)\right)\right) \]

Alternatives

Alternative 1
Error0.0
Cost13376
\[2 \cdot \tan^{-1} \left(\sqrt{\frac{1 - x}{1 + x}}\right) \]
Alternative 2
Error0.6
Cost13312
\[2 \cdot \tan^{-1} \left({\left(1 + x \cdot -0.3333333333333333\right)}^{3}\right) \]
Alternative 3
Error0.6
Cost6720
\[2 \cdot \tan^{-1} \left(1 - x\right) \]
Alternative 4
Error1.3
Cost6592
\[2 \cdot \tan^{-1} 1 \]

Error

Reproduce

herbie shell --seed 2022291 
(FPCore (x)
  :name "arccos"
  :precision binary64
  (* 2.0 (atan (sqrt (/ (- 1.0 x) (+ 1.0 x))))))