\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}\begin{array}{l}
\mathbf{if}\;x \le -7.26854291605878706 \cdot 10^{-16}:\\
\;\;\;\;\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x + x} - 1 \cdot 1}} \cdot \sqrt{e^{x} + 1}\\
\mathbf{else}:\\
\;\;\;\;\frac{{x}^{2}}{\sqrt{2}} \cdot \left(0.25 - \frac{0.125}{2}\right) + \left(\sqrt{2} + 0.5 \cdot \frac{x}{\sqrt{2}}\right)\\
\end{array}double f(double x) {
double r14797 = 2.0;
double r14798 = x;
double r14799 = r14797 * r14798;
double r14800 = exp(r14799);
double r14801 = 1.0;
double r14802 = r14800 - r14801;
double r14803 = exp(r14798);
double r14804 = r14803 - r14801;
double r14805 = r14802 / r14804;
double r14806 = sqrt(r14805);
return r14806;
}
double f(double x) {
double r14807 = x;
double r14808 = -7.268542916058787e-16;
bool r14809 = r14807 <= r14808;
double r14810 = 2.0;
double r14811 = r14810 * r14807;
double r14812 = exp(r14811);
double r14813 = 1.0;
double r14814 = r14812 - r14813;
double r14815 = r14807 + r14807;
double r14816 = exp(r14815);
double r14817 = r14813 * r14813;
double r14818 = r14816 - r14817;
double r14819 = r14814 / r14818;
double r14820 = sqrt(r14819);
double r14821 = exp(r14807);
double r14822 = r14821 + r14813;
double r14823 = sqrt(r14822);
double r14824 = r14820 * r14823;
double r14825 = 2.0;
double r14826 = pow(r14807, r14825);
double r14827 = sqrt(r14810);
double r14828 = r14826 / r14827;
double r14829 = 0.25;
double r14830 = 0.125;
double r14831 = r14830 / r14810;
double r14832 = r14829 - r14831;
double r14833 = r14828 * r14832;
double r14834 = 0.5;
double r14835 = r14807 / r14827;
double r14836 = r14834 * r14835;
double r14837 = r14827 + r14836;
double r14838 = r14833 + r14837;
double r14839 = r14809 ? r14824 : r14838;
return r14839;
}



Bits error versus x
Results
if x < -7.268542916058787e-16Initial program 0.7
rmApplied flip--0.5
Applied associate-/r/0.5
Applied sqrt-prod0.5
Simplified0.0
if -7.268542916058787e-16 < x Initial program 37.3
Taylor expanded around 0 7.3
Simplified7.3
Final simplification0.7
herbie shell --seed 2020046
(FPCore (x)
:name "sqrtexp (problem 3.4.4)"
:precision binary64
(sqrt (/ (- (exp (* 2 x)) 1) (- (exp x) 1))))