\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}\begin{array}{l}
\mathbf{if}\;x \le -3.639623849017884427727010081959901910409 \cdot 10^{-7}:\\
\;\;\;\;\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x + x} - 1 \cdot 1} \cdot \frac{{\left(e^{x}\right)}^{3} + {1}^{3}}{1 \cdot \left(1 - e^{x}\right) + e^{2 \cdot x}}}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{2 + x \cdot \left(0.5 \cdot x + 1\right)}\\
\end{array}double f(double x) {
double r20058 = 2.0;
double r20059 = x;
double r20060 = r20058 * r20059;
double r20061 = exp(r20060);
double r20062 = 1.0;
double r20063 = r20061 - r20062;
double r20064 = exp(r20059);
double r20065 = r20064 - r20062;
double r20066 = r20063 / r20065;
double r20067 = sqrt(r20066);
return r20067;
}
double f(double x) {
double r20068 = x;
double r20069 = -3.6396238490178844e-07;
bool r20070 = r20068 <= r20069;
double r20071 = 2.0;
double r20072 = r20071 * r20068;
double r20073 = exp(r20072);
double r20074 = 1.0;
double r20075 = r20073 - r20074;
double r20076 = r20068 + r20068;
double r20077 = exp(r20076);
double r20078 = r20074 * r20074;
double r20079 = r20077 - r20078;
double r20080 = r20075 / r20079;
double r20081 = exp(r20068);
double r20082 = 3.0;
double r20083 = pow(r20081, r20082);
double r20084 = pow(r20074, r20082);
double r20085 = r20083 + r20084;
double r20086 = r20074 - r20081;
double r20087 = r20074 * r20086;
double r20088 = 2.0;
double r20089 = r20088 * r20068;
double r20090 = exp(r20089);
double r20091 = r20087 + r20090;
double r20092 = r20085 / r20091;
double r20093 = r20080 * r20092;
double r20094 = sqrt(r20093);
double r20095 = 0.5;
double r20096 = r20095 * r20068;
double r20097 = r20096 + r20074;
double r20098 = r20068 * r20097;
double r20099 = r20071 + r20098;
double r20100 = sqrt(r20099);
double r20101 = r20070 ? r20094 : r20100;
return r20101;
}



Bits error versus x
Results
if x < -3.6396238490178844e-07Initial program 0.2
rmApplied flip--0.1
Applied associate-/r/0.1
Simplified0.0
rmApplied flip3-+0.0
Simplified0.0
if -3.6396238490178844e-07 < x Initial program 34.4
Taylor expanded around 0 6.6
Simplified6.6
Final simplification0.8
herbie shell --seed 2019325
(FPCore (x)
:name "sqrtexp (problem 3.4.4)"
:precision binary64
(sqrt (/ (- (exp (* 2 x)) 1) (- (exp x) 1))))