\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}\begin{array}{l}
\mathbf{if}\;x \le \frac{-906485597919399}{9444732965739290427392}:\\
\;\;\;\;\sqrt{\frac{\left(\sqrt{e^{2 \cdot x}} + \sqrt{1}\right) \cdot \left(\sqrt{e^{2 \cdot x}} - \sqrt{1}\right)}{\sqrt[3]{{\left(e^{x} - 1\right)}^{3}}}}\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{2} \cdot \frac{x}{\sqrt{2}} + \left(\sqrt{2} + \frac{{x}^{2}}{\sqrt{2}} \cdot \left(\frac{1}{4} - \frac{\frac{1}{8}}{2}\right)\right)\\
\end{array}double f(double x) {
double r34076 = 2.0;
double r34077 = x;
double r34078 = r34076 * r34077;
double r34079 = exp(r34078);
double r34080 = 1.0;
double r34081 = r34079 - r34080;
double r34082 = exp(r34077);
double r34083 = r34082 - r34080;
double r34084 = r34081 / r34083;
double r34085 = sqrt(r34084);
return r34085;
}
double f(double x) {
double r34086 = x;
double r34087 = -906485597919399.0;
double r34088 = 9.44473296573929e+21;
double r34089 = r34087 / r34088;
bool r34090 = r34086 <= r34089;
double r34091 = 2.0;
double r34092 = r34091 * r34086;
double r34093 = exp(r34092);
double r34094 = sqrt(r34093);
double r34095 = 1.0;
double r34096 = sqrt(r34095);
double r34097 = r34094 + r34096;
double r34098 = r34094 - r34096;
double r34099 = r34097 * r34098;
double r34100 = exp(r34086);
double r34101 = r34100 - r34095;
double r34102 = 3.0;
double r34103 = pow(r34101, r34102);
double r34104 = cbrt(r34103);
double r34105 = r34099 / r34104;
double r34106 = sqrt(r34105);
double r34107 = r34095 / r34091;
double r34108 = sqrt(r34091);
double r34109 = r34086 / r34108;
double r34110 = r34107 * r34109;
double r34111 = 2.0;
double r34112 = pow(r34086, r34111);
double r34113 = r34112 / r34108;
double r34114 = 4.0;
double r34115 = r34095 / r34114;
double r34116 = 8.0;
double r34117 = r34095 / r34116;
double r34118 = r34117 / r34091;
double r34119 = r34115 - r34118;
double r34120 = r34113 * r34119;
double r34121 = r34108 + r34120;
double r34122 = r34110 + r34121;
double r34123 = r34090 ? r34106 : r34122;
return r34123;
}



Bits error versus x
Results
if x < -9.597789595615565e-08Initial program 0.1
rmApplied add-sqr-sqrt0.1
Applied add-sqr-sqrt0.1
Applied difference-of-squares0.0
rmApplied add-cbrt-cube0.0
Simplified0.0
if -9.597789595615565e-08 < x Initial program 35.1
Taylor expanded around 0 7.8
Simplified7.8
Final simplification1.0
herbie shell --seed 197574269
(FPCore (x)
:name "sqrtexp (problem 3.4.4)"
:precision binary64
(sqrt (/ (- (exp (* 2 x)) 1) (- (exp x) 1))))