Average Error: 30.3 → 0.0
Time: 11.5s
Precision: 64
\[\frac{1 - \cos x}{\sin x}\]
\[\tan \left(\frac{x}{2}\right)\]
\frac{1 - \cos x}{\sin x}
\tan \left(\frac{x}{2}\right)
double f(double x) {
        double r1715196 = 1.0;
        double r1715197 = x;
        double r1715198 = cos(r1715197);
        double r1715199 = r1715196 - r1715198;
        double r1715200 = sin(r1715197);
        double r1715201 = r1715199 / r1715200;
        return r1715201;
}

double f(double x) {
        double r1715202 = x;
        double r1715203 = 2.0;
        double r1715204 = r1715202 / r1715203;
        double r1715205 = tan(r1715204);
        return r1715205;
}

Error

Bits error versus x

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Your Program's Arguments

Results

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Target

Original30.3
Target0.0
Herbie0.0
\[\tan \left(\frac{x}{2}\right)\]

Derivation

  1. Initial program 30.3

    \[\frac{1 - \cos x}{\sin x}\]
  2. Simplified0.0

    \[\leadsto \color{blue}{\tan \left(\frac{x}{2}\right)}\]
  3. Final simplification0.0

    \[\leadsto \tan \left(\frac{x}{2}\right)\]

Reproduce

herbie shell --seed 2019146 
(FPCore (x)
  :name "tanhf (example 3.4)"
  :herbie-expected 2

  :herbie-target
  (tan (/ x 2))

  (/ (- 1 (cos x)) (sin x)))