\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}\begin{array}{l}
\mathbf{if}\;x \le -4.54501292903996873 \cdot 10^{-10}:\\
\;\;\;\;\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x + x} - 1 \cdot 1}} \cdot \sqrt{e^{x} + 1}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{2 + x \cdot \left(0.5 \cdot x + 1\right)}\\
\end{array}double f(double x) {
double r19587 = 2.0;
double r19588 = x;
double r19589 = r19587 * r19588;
double r19590 = exp(r19589);
double r19591 = 1.0;
double r19592 = r19590 - r19591;
double r19593 = exp(r19588);
double r19594 = r19593 - r19591;
double r19595 = r19592 / r19594;
double r19596 = sqrt(r19595);
return r19596;
}
double f(double x) {
double r19597 = x;
double r19598 = -4.5450129290399687e-10;
bool r19599 = r19597 <= r19598;
double r19600 = 2.0;
double r19601 = r19600 * r19597;
double r19602 = exp(r19601);
double r19603 = 1.0;
double r19604 = r19602 - r19603;
double r19605 = r19597 + r19597;
double r19606 = exp(r19605);
double r19607 = r19603 * r19603;
double r19608 = r19606 - r19607;
double r19609 = r19604 / r19608;
double r19610 = sqrt(r19609);
double r19611 = exp(r19597);
double r19612 = r19611 + r19603;
double r19613 = sqrt(r19612);
double r19614 = r19610 * r19613;
double r19615 = 0.5;
double r19616 = r19615 * r19597;
double r19617 = r19616 + r19603;
double r19618 = r19597 * r19617;
double r19619 = r19600 + r19618;
double r19620 = sqrt(r19619);
double r19621 = r19599 ? r19614 : r19620;
return r19621;
}



Bits error versus x
Results
if x < -4.5450129290399687e-10Initial program 0.3
rmApplied flip--0.2
Applied associate-/r/0.2
Applied sqrt-prod0.2
Simplified0.0
if -4.5450129290399687e-10 < x Initial program 38.3
Taylor expanded around 0 7.0
Simplified7.0
Final simplification0.8
herbie shell --seed 2019199
(FPCore (x)
:name "sqrtexp (problem 3.4.4)"
(sqrt (/ (- (exp (* 2.0 x)) 1.0) (- (exp x) 1.0))))