\frac{x - \sin x}{x - \tan x}\begin{array}{l}
\mathbf{if}\;x \le -0.024514420160319003 \lor \neg \left(x \le 0.0285174389981211092\right):\\
\;\;\;\;\frac{x - \sin x}{x - \tan x}\\
\mathbf{else}:\\
\;\;\;\;\left(\frac{9}{40} \cdot {x}^{2} - \frac{27}{2800} \cdot {x}^{4}\right) - \frac{1}{2}\\
\end{array}double f(double x) {
double r7778 = x;
double r7779 = sin(r7778);
double r7780 = r7778 - r7779;
double r7781 = tan(r7778);
double r7782 = r7778 - r7781;
double r7783 = r7780 / r7782;
return r7783;
}
double f(double x) {
double r7784 = x;
double r7785 = -0.024514420160319003;
bool r7786 = r7784 <= r7785;
double r7787 = 0.02851743899812111;
bool r7788 = r7784 <= r7787;
double r7789 = !r7788;
bool r7790 = r7786 || r7789;
double r7791 = sin(r7784);
double r7792 = r7784 - r7791;
double r7793 = tan(r7784);
double r7794 = r7784 - r7793;
double r7795 = r7792 / r7794;
double r7796 = 0.225;
double r7797 = 2.0;
double r7798 = pow(r7784, r7797);
double r7799 = r7796 * r7798;
double r7800 = 0.009642857142857142;
double r7801 = 4.0;
double r7802 = pow(r7784, r7801);
double r7803 = r7800 * r7802;
double r7804 = r7799 - r7803;
double r7805 = 0.5;
double r7806 = r7804 - r7805;
double r7807 = r7790 ? r7795 : r7806;
return r7807;
}



Bits error versus x
Results
if x < -0.024514420160319003 or 0.02851743899812111 < x Initial program 0.1
if -0.024514420160319003 < x < 0.02851743899812111Initial program 63.2
Taylor expanded around 0 0.0
rmApplied associate--r+0.0
Final simplification0.0
herbie shell --seed 2020020
(FPCore (x)
:name "sintan (problem 3.4.5)"
:precision binary64
(/ (- x (sin x)) (- x (tan x))))