\frac{x - \sin x}{x - \tan x}\begin{array}{l}
\mathbf{if}\;x \le -2.4051902967603365:\\
\;\;\;\;\left(\frac{\frac{\sin x}{\cos x}}{x} \cdot \frac{\frac{\sin x}{\cos x}}{x} + \left(\left(1 - \frac{\sin x}{x}\right) + \frac{\frac{\sin x}{x}}{\cos x}\right)\right) - \frac{\sin x}{x \cdot x} \cdot \frac{\sin x}{\cos x}\\
\mathbf{elif}\;x \le 7.937565998741664:\\
\;\;\;\;\left(x \cdot x\right) \cdot \left(\frac{9}{40} - \left(x \cdot x\right) \cdot \frac{27}{2800}\right) - \frac{1}{2}\\
\mathbf{else}:\\
\;\;\;\;\left(\frac{\frac{\sin x}{\cos x}}{x} \cdot \frac{\frac{\sin x}{\cos x}}{x} + \left(\left(1 - \frac{\sin x}{x}\right) + \frac{\frac{\sin x}{x}}{\cos x}\right)\right) - \frac{\sin x}{x \cdot x} \cdot \frac{\sin x}{\cos x}\\
\end{array}double f(double x) {
double r619973 = x;
double r619974 = sin(r619973);
double r619975 = r619973 - r619974;
double r619976 = tan(r619973);
double r619977 = r619973 - r619976;
double r619978 = r619975 / r619977;
return r619978;
}
double f(double x) {
double r619979 = x;
double r619980 = -2.4051902967603365;
bool r619981 = r619979 <= r619980;
double r619982 = sin(r619979);
double r619983 = cos(r619979);
double r619984 = r619982 / r619983;
double r619985 = r619984 / r619979;
double r619986 = r619985 * r619985;
double r619987 = 1.0;
double r619988 = r619982 / r619979;
double r619989 = r619987 - r619988;
double r619990 = r619988 / r619983;
double r619991 = r619989 + r619990;
double r619992 = r619986 + r619991;
double r619993 = r619979 * r619979;
double r619994 = r619982 / r619993;
double r619995 = r619994 * r619984;
double r619996 = r619992 - r619995;
double r619997 = 7.937565998741664;
bool r619998 = r619979 <= r619997;
double r619999 = 0.225;
double r620000 = 0.009642857142857142;
double r620001 = r619993 * r620000;
double r620002 = r619999 - r620001;
double r620003 = r619993 * r620002;
double r620004 = 0.5;
double r620005 = r620003 - r620004;
double r620006 = r619998 ? r620005 : r619996;
double r620007 = r619981 ? r619996 : r620006;
return r620007;
}



Bits error versus x
Results
if x < -2.4051902967603365 or 7.937565998741664 < x Initial program 0.0
Taylor expanded around -inf 0.4
Simplified0.4
if -2.4051902967603365 < x < 7.937565998741664Initial program 62.5
Taylor expanded around 0 0.2
Simplified0.2
Final simplification0.3
herbie shell --seed 2019142
(FPCore (x)
:name "sintan (problem 3.4.5)"
(/ (- x (sin x)) (- x (tan x))))