Average Error: 58.2 → 0.0
Time: 27.2s
Precision: 64
\[\frac{e^{x} - e^{-x}}{e^{x} + e^{-x}}\]
↓
\[\tanh x\]
\frac{e^{x} - e^{-x}}{e^{x} + e^{-x}}
↓
\tanh x
double f(double x) {
        double r29207 = x;
        double r29208 = exp(r29207);
        double r29209 = -r29207;
        double r29210 = exp(r29209);
        double r29211 = r29208 - r29210;
        double r29212 = r29208 + r29210;
        double r29213 = r29211 / r29212;
        return r29213;
}
↓
double f(double x) {
        double r29214 = x;
        double r29215 = tanh(r29214);
        return r29215;
}

Error

Bits error versus x

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Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Initial program 58.2

    \[\frac{e^{x} - e^{-x}}{e^{x} + e^{-x}}\]
  2. Using strategy rm

  3. Applied tanh-undef0.0

    \[\leadsto \color{blue}{\tanh x}\]

  4. Final simplification0.0

    \[\leadsto \tanh x\]

Reproduce

herbie shell --seed 2019323 
(FPCore (x)
  :name "Hyperbolic tangent"
  :precision binary64
  (/ (- (exp x) (exp (- x))) (+ (exp x) (exp (- x)))))