\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}\begin{array}{l}
\mathbf{if}\;x \le -2.5679454952614643 \cdot 10^{-15}:\\
\;\;\;\;\sqrt{\frac{e^{2 \cdot x} - 1}{\sqrt[3]{{\left(e^{x + x} - 1 \cdot 1\right)}^{3}}} \cdot \left(e^{x} + 1\right)}\\
\mathbf{else}:\\
\;\;\;\;\left(0.25 \cdot \frac{{x}^{2}}{\sqrt{2}} + \left(\sqrt{2} + 0.5 \cdot \frac{x}{\sqrt{2}}\right)\right) - 0.125 \cdot \frac{{x}^{2}}{{\left(\sqrt{2}\right)}^{3}}\\
\end{array}double f(double x) {
double r19897 = 2.0;
double r19898 = x;
double r19899 = r19897 * r19898;
double r19900 = exp(r19899);
double r19901 = 1.0;
double r19902 = r19900 - r19901;
double r19903 = exp(r19898);
double r19904 = r19903 - r19901;
double r19905 = r19902 / r19904;
double r19906 = sqrt(r19905);
return r19906;
}
double f(double x) {
double r19907 = x;
double r19908 = -2.5679454952614643e-15;
bool r19909 = r19907 <= r19908;
double r19910 = 2.0;
double r19911 = r19910 * r19907;
double r19912 = exp(r19911);
double r19913 = 1.0;
double r19914 = r19912 - r19913;
double r19915 = r19907 + r19907;
double r19916 = exp(r19915);
double r19917 = r19913 * r19913;
double r19918 = r19916 - r19917;
double r19919 = 3.0;
double r19920 = pow(r19918, r19919);
double r19921 = cbrt(r19920);
double r19922 = r19914 / r19921;
double r19923 = exp(r19907);
double r19924 = r19923 + r19913;
double r19925 = r19922 * r19924;
double r19926 = sqrt(r19925);
double r19927 = 0.25;
double r19928 = 2.0;
double r19929 = pow(r19907, r19928);
double r19930 = sqrt(r19910);
double r19931 = r19929 / r19930;
double r19932 = r19927 * r19931;
double r19933 = 0.5;
double r19934 = r19907 / r19930;
double r19935 = r19933 * r19934;
double r19936 = r19930 + r19935;
double r19937 = r19932 + r19936;
double r19938 = 0.125;
double r19939 = pow(r19930, r19919);
double r19940 = r19929 / r19939;
double r19941 = r19938 * r19940;
double r19942 = r19937 - r19941;
double r19943 = r19909 ? r19926 : r19942;
return r19943;
}



Bits error versus x
Results
if x < -2.5679454952614643e-15Initial program 0.7
rmApplied flip--0.4
Applied associate-/r/0.4
Simplified0.0
rmApplied add-cbrt-cube0.0
Simplified0.0
if -2.5679454952614643e-15 < x Initial program 38.5
rmApplied flip--36.1
Applied associate-/r/36.1
Simplified29.1
rmApplied add-cbrt-cube29.5
Simplified29.5
Taylor expanded around 0 7.4
Final simplification0.7
herbie shell --seed 2020045
(FPCore (x)
:name "sqrtexp (problem 3.4.4)"
:precision binary64
(sqrt (/ (- (exp (* 2 x)) 1) (- (exp x) 1))))