\frac{x}{x + 1} - \frac{x + 1}{x - 1}\begin{array}{l}
\mathbf{if}\;x \le -11192.06208307448832783848047256469726562 \lor \neg \left(x \le 7503.829948731607146328315138816833496094\right):\\
\;\;\;\;-\left(\left(\frac{1}{x \cdot x} + \frac{3}{x}\right) + \frac{3}{{x}^{3}}\right)\\
\mathbf{else}:\\
\;\;\;\;\frac{x}{x + 1} - \frac{\frac{1 + x}{\sqrt[3]{x - 1} \cdot \sqrt[3]{x - 1}}}{\sqrt[3]{x - 1}}\\
\end{array}double f(double x) {
double r89723 = x;
double r89724 = 1.0;
double r89725 = r89723 + r89724;
double r89726 = r89723 / r89725;
double r89727 = r89723 - r89724;
double r89728 = r89725 / r89727;
double r89729 = r89726 - r89728;
return r89729;
}
double f(double x) {
double r89730 = x;
double r89731 = -11192.062083074488;
bool r89732 = r89730 <= r89731;
double r89733 = 7503.829948731607;
bool r89734 = r89730 <= r89733;
double r89735 = !r89734;
bool r89736 = r89732 || r89735;
double r89737 = 1.0;
double r89738 = r89730 * r89730;
double r89739 = r89737 / r89738;
double r89740 = 3.0;
double r89741 = r89740 / r89730;
double r89742 = r89739 + r89741;
double r89743 = 3.0;
double r89744 = pow(r89730, r89743);
double r89745 = r89740 / r89744;
double r89746 = r89742 + r89745;
double r89747 = -r89746;
double r89748 = r89730 + r89737;
double r89749 = r89730 / r89748;
double r89750 = r89737 + r89730;
double r89751 = r89730 - r89737;
double r89752 = cbrt(r89751);
double r89753 = r89752 * r89752;
double r89754 = r89750 / r89753;
double r89755 = r89754 / r89752;
double r89756 = r89749 - r89755;
double r89757 = r89736 ? r89747 : r89756;
return r89757;
}



Bits error versus x
Results
if x < -11192.062083074488 or 7503.829948731607 < x Initial program 59.4
Simplified59.4
rmApplied add-cube-cbrt60.3
Applied associate-/r*60.3
Taylor expanded around inf 0.3
Simplified0.0
if -11192.062083074488 < x < 7503.829948731607Initial program 0.1
Simplified0.1
rmApplied add-cube-cbrt0.1
Applied associate-/r*0.1
Final simplification0.1
herbie shell --seed 2019208
(FPCore (x)
:name "Asymptote C"
:precision binary64
(- (/ x (+ x 1)) (/ (+ x 1) (- x 1))))