\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}\begin{array}{l}
\mathbf{if}\;x \le -1.48512766100304831 \cdot 10^{-5}:\\
\;\;\;\;\sqrt{\frac{e^{2 \cdot x} - 1}{\mathsf{fma}\left(-1, 1, e^{x + x}\right)} \cdot \mathsf{fma}\left(\sqrt[3]{e^{x}} \cdot \sqrt[3]{e^{x}}, \sqrt[3]{e^{x}}, 1\right)}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{\mathsf{fma}\left(0.5, {x}^{2}, \mathsf{fma}\left(1, x, 2\right)\right)}\\
\end{array}double f(double x) {
double r14892 = 2.0;
double r14893 = x;
double r14894 = r14892 * r14893;
double r14895 = exp(r14894);
double r14896 = 1.0;
double r14897 = r14895 - r14896;
double r14898 = exp(r14893);
double r14899 = r14898 - r14896;
double r14900 = r14897 / r14899;
double r14901 = sqrt(r14900);
return r14901;
}
double f(double x) {
double r14902 = x;
double r14903 = -1.4851276610030483e-05;
bool r14904 = r14902 <= r14903;
double r14905 = 2.0;
double r14906 = r14905 * r14902;
double r14907 = exp(r14906);
double r14908 = 1.0;
double r14909 = r14907 - r14908;
double r14910 = -r14908;
double r14911 = r14902 + r14902;
double r14912 = exp(r14911);
double r14913 = fma(r14910, r14908, r14912);
double r14914 = r14909 / r14913;
double r14915 = exp(r14902);
double r14916 = cbrt(r14915);
double r14917 = r14916 * r14916;
double r14918 = fma(r14917, r14916, r14908);
double r14919 = r14914 * r14918;
double r14920 = sqrt(r14919);
double r14921 = 0.5;
double r14922 = 2.0;
double r14923 = pow(r14902, r14922);
double r14924 = fma(r14908, r14902, r14905);
double r14925 = fma(r14921, r14923, r14924);
double r14926 = sqrt(r14925);
double r14927 = r14904 ? r14920 : r14926;
return r14927;
}



Bits error versus x
if x < -1.4851276610030483e-05Initial program 0.1
rmApplied flip--0.0
Applied associate-/r/0.0
Simplified0.0
rmApplied add-cube-cbrt0.0
Applied fma-def0.0
if -1.4851276610030483e-05 < x Initial program 34.8
Taylor expanded around 0 6.3
Simplified6.3
Final simplification0.8
herbie shell --seed 2020036 +o rules:numerics
(FPCore (x)
:name "sqrtexp (problem 3.4.4)"
:precision binary64
(sqrt (/ (- (exp (* 2 x)) 1) (- (exp x) 1))))