\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}\begin{array}{l}
\mathbf{if}\;x \le -7.5425646206775067 \cdot 10^{-11}:\\
\;\;\;\;\sqrt{\frac{\sqrt[3]{{\left(e^{2 \cdot x} - 1\right)}^{3}}}{\frac{e^{2 \cdot x} - 1 \cdot 1}{e^{x} + 1}}}\\
\mathbf{else}:\\
\;\;\;\;0.5 \cdot \frac{x}{\sqrt{2}} + \left(\sqrt{2} + \frac{{x}^{2}}{\sqrt{2}} \cdot \left(0.25 - \frac{0.125}{2}\right)\right)\\
\end{array}double f(double x) {
double r12560 = 2.0;
double r12561 = x;
double r12562 = r12560 * r12561;
double r12563 = exp(r12562);
double r12564 = 1.0;
double r12565 = r12563 - r12564;
double r12566 = exp(r12561);
double r12567 = r12566 - r12564;
double r12568 = r12565 / r12567;
double r12569 = sqrt(r12568);
return r12569;
}
double f(double x) {
double r12570 = x;
double r12571 = -7.542564620677507e-11;
bool r12572 = r12570 <= r12571;
double r12573 = 2.0;
double r12574 = r12573 * r12570;
double r12575 = exp(r12574);
double r12576 = 1.0;
double r12577 = r12575 - r12576;
double r12578 = 3.0;
double r12579 = pow(r12577, r12578);
double r12580 = cbrt(r12579);
double r12581 = 2.0;
double r12582 = r12581 * r12570;
double r12583 = exp(r12582);
double r12584 = r12576 * r12576;
double r12585 = r12583 - r12584;
double r12586 = exp(r12570);
double r12587 = r12586 + r12576;
double r12588 = r12585 / r12587;
double r12589 = r12580 / r12588;
double r12590 = sqrt(r12589);
double r12591 = 0.5;
double r12592 = sqrt(r12573);
double r12593 = r12570 / r12592;
double r12594 = r12591 * r12593;
double r12595 = pow(r12570, r12581);
double r12596 = r12595 / r12592;
double r12597 = 0.25;
double r12598 = 0.125;
double r12599 = r12598 / r12573;
double r12600 = r12597 - r12599;
double r12601 = r12596 * r12600;
double r12602 = r12592 + r12601;
double r12603 = r12594 + r12602;
double r12604 = r12572 ? r12590 : r12603;
return r12604;
}



Bits error versus x
Results
if x < -7.542564620677507e-11Initial program 0.4
rmApplied flip--0.2
rmApplied prod-exp0.0
Simplified0.0
rmApplied add-cbrt-cube0.0
Simplified0.0
if -7.542564620677507e-11 < x Initial program 36.8
Taylor expanded around 0 7.5
Simplified7.5
Final simplification0.9
herbie shell --seed 2020039
(FPCore (x)
:name "sqrtexp (problem 3.4.4)"
:precision binary64
(sqrt (/ (- (exp (* 2 x)) 1) (- (exp x) 1))))