\frac{x - \sin x}{x - \tan x}\begin{array}{l}
\mathbf{if}\;x \le -0.028868508597387585:\\
\;\;\;\;\frac{x}{x - \tan x} - \frac{\sin x}{x - \tan x}\\
\mathbf{elif}\;x \le 0.027208711435501284:\\
\;\;\;\;\frac{9}{40} \cdot {x}^{2} - \left(\frac{27}{2800} \cdot {x}^{4} + \frac{1}{2}\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt[3]{\sqrt[3]{{\left({\left(\frac{x - \sin x}{x - \tan x}\right)}^{3}\right)}^{3}}}\\
\end{array}double f(double x) {
double r14979 = x;
double r14980 = sin(r14979);
double r14981 = r14979 - r14980;
double r14982 = tan(r14979);
double r14983 = r14979 - r14982;
double r14984 = r14981 / r14983;
return r14984;
}
double f(double x) {
double r14985 = x;
double r14986 = -0.028868508597387585;
bool r14987 = r14985 <= r14986;
double r14988 = tan(r14985);
double r14989 = r14985 - r14988;
double r14990 = r14985 / r14989;
double r14991 = sin(r14985);
double r14992 = r14991 / r14989;
double r14993 = r14990 - r14992;
double r14994 = 0.027208711435501284;
bool r14995 = r14985 <= r14994;
double r14996 = 0.225;
double r14997 = 2.0;
double r14998 = pow(r14985, r14997);
double r14999 = r14996 * r14998;
double r15000 = 0.009642857142857142;
double r15001 = 4.0;
double r15002 = pow(r14985, r15001);
double r15003 = r15000 * r15002;
double r15004 = 0.5;
double r15005 = r15003 + r15004;
double r15006 = r14999 - r15005;
double r15007 = r14985 - r14991;
double r15008 = r15007 / r14989;
double r15009 = 3.0;
double r15010 = pow(r15008, r15009);
double r15011 = pow(r15010, r15009);
double r15012 = cbrt(r15011);
double r15013 = cbrt(r15012);
double r15014 = r14995 ? r15006 : r15013;
double r15015 = r14987 ? r14993 : r15014;
return r15015;
}



Bits error versus x
Results
if x < -0.028868508597387585Initial program 0.0
rmApplied div-sub0.1
if -0.028868508597387585 < x < 0.027208711435501284Initial program 63.0
Taylor expanded around 0 0.0
if 0.027208711435501284 < x Initial program 0.1
rmApplied add-cbrt-cube40.9
Applied add-cbrt-cube42.1
Applied cbrt-undiv42.1
Simplified0.1
rmApplied add-cbrt-cube0.1
Simplified0.1
Final simplification0.0
herbie shell --seed 2020057
(FPCore (x)
:name "sintan (problem 3.4.5)"
:precision binary64
(/ (- x (sin x)) (- x (tan x))))