\frac{x}{x + 1} - \frac{x + 1}{x - 1}\begin{array}{l}
\mathbf{if}\;x \le -11931.4119690201605 \lor \neg \left(x \le 12679.85899306799\right):\\
\;\;\;\;\frac{-1}{x \cdot x} - \left(\frac{3}{{x}^{3}} + \frac{3}{x}\right)\\
\mathbf{else}:\\
\;\;\;\;\frac{\left(x \cdot x\right) \cdot \left(\left(x - 1\right) \cdot \left(x - 1\right)\right) - \left(\left(x + 1\right) \cdot \left(x + 1\right)\right) \cdot \left(\left(x + 1\right) \cdot \left(x + 1\right)\right)}{\left(\frac{x}{x + 1} + \frac{x + 1}{x - 1}\right) \cdot \left(\left(\left(x + 1\right) \cdot \left(x + 1\right)\right) \cdot \left(\left(x - 1\right) \cdot \left(x - 1\right)\right)\right)}\\
\end{array}double f(double x) {
double r97731 = x;
double r97732 = 1.0;
double r97733 = r97731 + r97732;
double r97734 = r97731 / r97733;
double r97735 = r97731 - r97732;
double r97736 = r97733 / r97735;
double r97737 = r97734 - r97736;
return r97737;
}
double f(double x) {
double r97738 = x;
double r97739 = -11931.41196902016;
bool r97740 = r97738 <= r97739;
double r97741 = 12679.85899306799;
bool r97742 = r97738 <= r97741;
double r97743 = !r97742;
bool r97744 = r97740 || r97743;
double r97745 = 1.0;
double r97746 = -r97745;
double r97747 = r97738 * r97738;
double r97748 = r97746 / r97747;
double r97749 = 3.0;
double r97750 = 3.0;
double r97751 = pow(r97738, r97750);
double r97752 = r97749 / r97751;
double r97753 = r97749 / r97738;
double r97754 = r97752 + r97753;
double r97755 = r97748 - r97754;
double r97756 = r97738 - r97745;
double r97757 = r97756 * r97756;
double r97758 = r97747 * r97757;
double r97759 = r97738 + r97745;
double r97760 = r97759 * r97759;
double r97761 = r97760 * r97760;
double r97762 = r97758 - r97761;
double r97763 = r97738 / r97759;
double r97764 = r97759 / r97756;
double r97765 = r97763 + r97764;
double r97766 = r97760 * r97757;
double r97767 = r97765 * r97766;
double r97768 = r97762 / r97767;
double r97769 = r97744 ? r97755 : r97768;
return r97769;
}



Bits error versus x
Results
if x < -11931.41196902016 or 12679.85899306799 < x Initial program 59.3
Taylor expanded around inf 0.3
Simplified0.0
if -11931.41196902016 < x < 12679.85899306799Initial program 0.1
rmApplied flip--0.1
rmApplied frac-times0.1
Applied frac-times0.1
Applied frac-sub0.1
Applied associate-/l/0.1
Final simplification0.1
herbie shell --seed 2020047
(FPCore (x)
:name "Asymptote C"
:precision binary64
(- (/ x (+ x 1)) (/ (+ x 1) (- x 1))))