\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}\begin{array}{l}
\mathbf{if}\;x \le -1.582886078662358144753842525975784383263 \cdot 10^{-5} \lor \neg \left(x \le 3.955846843948518696530453498533264067305 \cdot 10^{-7}\right):\\
\;\;\;\;\sqrt{\frac{\sqrt{e^{2 \cdot x}} + \sqrt{1}}{1}} \cdot \sqrt{\frac{\sqrt{e^{2 \cdot x}} - \sqrt{1}}{e^{x} - 1}}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{x \cdot \left(1 + 0.5 \cdot x\right) + 2}\\
\end{array}double f(double x) {
double r8652 = 2.0;
double r8653 = x;
double r8654 = r8652 * r8653;
double r8655 = exp(r8654);
double r8656 = 1.0;
double r8657 = r8655 - r8656;
double r8658 = exp(r8653);
double r8659 = r8658 - r8656;
double r8660 = r8657 / r8659;
double r8661 = sqrt(r8660);
return r8661;
}
double f(double x) {
double r8662 = x;
double r8663 = -1.582886078662358e-05;
bool r8664 = r8662 <= r8663;
double r8665 = 3.9558468439485187e-07;
bool r8666 = r8662 <= r8665;
double r8667 = !r8666;
bool r8668 = r8664 || r8667;
double r8669 = 2.0;
double r8670 = r8669 * r8662;
double r8671 = exp(r8670);
double r8672 = sqrt(r8671);
double r8673 = 1.0;
double r8674 = sqrt(r8673);
double r8675 = r8672 + r8674;
double r8676 = 1.0;
double r8677 = r8675 / r8676;
double r8678 = sqrt(r8677);
double r8679 = r8672 - r8674;
double r8680 = exp(r8662);
double r8681 = r8680 - r8673;
double r8682 = r8679 / r8681;
double r8683 = sqrt(r8682);
double r8684 = r8678 * r8683;
double r8685 = 0.5;
double r8686 = r8685 * r8662;
double r8687 = r8673 + r8686;
double r8688 = r8662 * r8687;
double r8689 = r8688 + r8669;
double r8690 = sqrt(r8689);
double r8691 = r8668 ? r8684 : r8690;
return r8691;
}



Bits error versus x
Results
if x < -1.582886078662358e-05 or 3.9558468439485187e-07 < x Initial program 0.3
rmApplied *-un-lft-identity0.3
Applied add-sqr-sqrt0.3
Applied add-sqr-sqrt0.3
Applied difference-of-squares0.1
Applied times-frac0.1
Applied sqrt-prod0.1
if -1.582886078662358e-05 < x < 3.9558468439485187e-07Initial program 40.4
Taylor expanded around 0 0.1
Simplified0.1
Final simplification0.1
herbie shell --seed 2019346
(FPCore (x)
:name "sqrtexp (problem 3.4.4)"
:precision binary64
(sqrt (/ (- (exp (* 2 x)) 1) (- (exp x) 1))))