\frac{x - \sin x}{x - \tan x}\begin{array}{l}
\mathbf{if}\;x \le -0.0268909451166995696 \lor \neg \left(x \le 0.025959275320095801\right):\\
\;\;\;\;\frac{x - \sin x}{x - \frac{\sin x}{\cos x}}\\
\mathbf{else}:\\
\;\;\;\;\frac{9}{40} \cdot {x}^{2} - \left(\frac{27}{2800} \cdot {x}^{4} + \frac{1}{2}\right)\\
\end{array}double f(double x) {
double r11783 = x;
double r11784 = sin(r11783);
double r11785 = r11783 - r11784;
double r11786 = tan(r11783);
double r11787 = r11783 - r11786;
double r11788 = r11785 / r11787;
return r11788;
}
double f(double x) {
double r11789 = x;
double r11790 = -0.02689094511669957;
bool r11791 = r11789 <= r11790;
double r11792 = 0.0259592753200958;
bool r11793 = r11789 <= r11792;
double r11794 = !r11793;
bool r11795 = r11791 || r11794;
double r11796 = sin(r11789);
double r11797 = r11789 - r11796;
double r11798 = cos(r11789);
double r11799 = r11796 / r11798;
double r11800 = r11789 - r11799;
double r11801 = r11797 / r11800;
double r11802 = 0.225;
double r11803 = 2.0;
double r11804 = pow(r11789, r11803);
double r11805 = r11802 * r11804;
double r11806 = 0.009642857142857142;
double r11807 = 4.0;
double r11808 = pow(r11789, r11807);
double r11809 = r11806 * r11808;
double r11810 = 0.5;
double r11811 = r11809 + r11810;
double r11812 = r11805 - r11811;
double r11813 = r11795 ? r11801 : r11812;
return r11813;
}



Bits error versus x
Results
if x < -0.02689094511669957 or 0.0259592753200958 < x Initial program 0.0
Taylor expanded around inf 0.0
if -0.02689094511669957 < x < 0.0259592753200958Initial program 63.3
Taylor expanded around 0 0.0
Final simplification0.0
herbie shell --seed 2020035
(FPCore (x)
:name "sintan (problem 3.4.5)"
:precision binary64
(/ (- x (sin x)) (- x (tan x))))