Average Error: 31.4 → 0.0
Time: 10.2s
Precision: binary64
\[\frac{x - \sin x}{x - \tan x}\]
↓
\[\begin{array}{l} \mathbf{if}\;x \leq -0.026474350661182082:\\ \;\;\;\;\frac{x - \sin x}{x - \tan x}\\ \mathbf{elif}\;x \leq 0.029194764836342937:\\ \;\;\;\;\left(-0.5 + \left(x \cdot x\right) \cdot 0.225\right) - 0.009642857142857142 \cdot {x}^{4}\\ \mathbf{else}:\\ \;\;\;\;\log \left(e^{\frac{x - \sin x}{x - \tan x}}\right)\\ \end{array}\]
\frac{x - \sin x}{x - \tan x}
↓
\begin{array}{l}
\mathbf{if}\;x \leq -0.026474350661182082:\\
\;\;\;\;\frac{x - \sin x}{x - \tan x}\\

\mathbf{elif}\;x \leq 0.029194764836342937:\\
\;\;\;\;\left(-0.5 + \left(x \cdot x\right) \cdot 0.225\right) - 0.009642857142857142 \cdot {x}^{4}\\

\mathbf{else}:\\
\;\;\;\;\log \left(e^{\frac{x - \sin x}{x - \tan x}}\right)\\

\end{array}
(FPCore (x) :precision binary64 (/ (- x (sin x)) (- x (tan x))))
↓
(FPCore (x)
 :precision binary64
 (if (<= x -0.026474350661182082)
   (/ (- x (sin x)) (- x (tan x)))
   (if (<= x 0.029194764836342937)
     (- (+ -0.5 (* (* x x) 0.225)) (* 0.009642857142857142 (pow x 4.0)))
     (log (exp (/ (- x (sin x)) (- x (tan x))))))))
double code(double x) {
	return (x - sin(x)) / (x - tan(x));
}
↓
double code(double x) {
	double tmp;
	if (x <= -0.026474350661182082) {
		tmp = (x - sin(x)) / (x - tan(x));
	} else if (x <= 0.029194764836342937) {
		tmp = (-0.5 + ((x * x) * 0.225)) - (0.009642857142857142 * pow(x, 4.0));
	} else {
		tmp = log(exp((x - sin(x)) / (x - tan(x))));
	}
	return tmp;
}

Error

Bits error versus x

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Split input into 3 regimes

  2. if x < -0.026474350661182082

    1. Initial program 0.0

      \[\frac{x - \sin x}{x - \tan x}\]

    if -0.026474350661182082 < x < 0.029194764836342937

    1. Initial program 63.3

      \[\frac{x - \sin x}{x - \tan x}\]
    2. Using strategy rm

    3. Applied add-log-exp_binary6463.3

      \[\leadsto \color{blue}{\log \left(e^{\frac{x - \sin x}{x - \tan x}}\right)}\]

    4. Taylor expanded around 0 0.0

      \[\leadsto \color{blue}{\left(\log \left(e^{-0.5}\right) + 0.225 \cdot {x}^{2}\right) - 0.009642857142857142 \cdot {x}^{4}}\]

    5. Simplified0.0

      \[\leadsto \color{blue}{\left(-0.5 + \left(x \cdot x\right) \cdot 0.225\right) - 0.009642857142857142 \cdot {x}^{4}}\]

    if 0.029194764836342937 < x

    1. Initial program 0.1

      \[\frac{x - \sin x}{x - \tan x}\]
    2. Using strategy rm

    3. Applied add-log-exp_binary640.1

      \[\leadsto \color{blue}{\log \left(e^{\frac{x - \sin x}{x - \tan x}}\right)}\]
  3. Recombined 3 regimes into one program.

  4. Final simplification0.0

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -0.026474350661182082:\\ \;\;\;\;\frac{x - \sin x}{x - \tan x}\\ \mathbf{elif}\;x \leq 0.029194764836342937:\\ \;\;\;\;\left(-0.5 + \left(x \cdot x\right) \cdot 0.225\right) - 0.009642857142857142 \cdot {x}^{4}\\ \mathbf{else}:\\ \;\;\;\;\log \left(e^{\frac{x - \sin x}{x - \tan x}}\right)\\ \end{array}\]

Reproduce

herbie shell --seed 2020343 
(FPCore (x)
  :name "sintan (problem 3.4.5)"
  :precision binary64
  (/ (- x (sin x)) (- x (tan x))))