Average Error: 37.6 → 0.4
Time: 6.4s
Precision: 64
\[\sin \left(x + \varepsilon\right) - \sin x\]
↓
\[\frac{\sin x \cdot \left({\left(\cos \varepsilon\right)}^{3} - 1\right)}{\cos \varepsilon \cdot \cos \varepsilon + \left(1 + \cos \varepsilon \cdot 1\right)} + \cos x \cdot \sin \varepsilon\]
\sin \left(x + \varepsilon\right) - \sin x
↓
\frac{\sin x \cdot \left({\left(\cos \varepsilon\right)}^{3} - 1\right)}{\cos \varepsilon \cdot \cos \varepsilon + \left(1 + \cos \varepsilon \cdot 1\right)} + \cos x \cdot \sin \varepsilon
double f(double x, double eps) {
        double r91577 = x;
        double r91578 = eps;
        double r91579 = r91577 + r91578;
        double r91580 = sin(r91579);
        double r91581 = sin(r91577);
        double r91582 = r91580 - r91581;
        return r91582;
}
↓
double f(double x, double eps) {
        double r91583 = x;
        double r91584 = sin(r91583);
        double r91585 = eps;
        double r91586 = cos(r91585);
        double r91587 = 3.0;
        double r91588 = pow(r91586, r91587);
        double r91589 = 1.0;
        double r91590 = r91588 - r91589;
        double r91591 = r91584 * r91590;
        double r91592 = r91586 * r91586;
        double r91593 = r91586 * r91589;
        double r91594 = r91589 + r91593;
        double r91595 = r91592 + r91594;
        double r91596 = r91591 / r91595;
        double r91597 = cos(r91583);
        double r91598 = sin(r91585);
        double r91599 = r91597 * r91598;
        double r91600 = r91596 + r91599;
        return r91600;
}

Error

Bits error versus x

Bits error versus eps

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Target

Original37.6
Target15.4
Herbie0.4
\[2 \cdot \left(\cos \left(x + \frac{\varepsilon}{2}\right) \cdot \sin \left(\frac{\varepsilon}{2}\right)\right)\]

Derivation

  1. Initial program 37.6

    \[\sin \left(x + \varepsilon\right) - \sin x\]
  2. Using strategy rm

  3. Applied sin-sum22.1

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

  4. Applied associate--l+22.1

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

  5. Taylor expanded around inf 22.1

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

  6. Simplified0.4

    \[\leadsto \color{blue}{\mathsf{fma}\left(\sin x, \cos \varepsilon - 1, \cos x \cdot \sin \varepsilon\right)}\]
  7. Using strategy rm

  8. Applied fma-udef0.4

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

  10. Applied flip3--0.4

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

  11. Applied associate-*r/0.4

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

  12. Simplified0.4

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

  13. Final simplification0.4

    \[\leadsto \frac{\sin x \cdot \left({\left(\cos \varepsilon\right)}^{3} - 1\right)}{\cos \varepsilon \cdot \cos \varepsilon + \left(1 + \cos \varepsilon \cdot 1\right)} + \cos x \cdot \sin \varepsilon\]

Reproduce

herbie shell --seed 2020036 +o rules:numerics
(FPCore (x eps)
  :name "2sin (example 3.3)"
  :precision binary64

  :herbie-target
  (* 2 (* (cos (+ x (/ eps 2))) (sin (/ eps 2))))

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