\frac{2}{e^{x} + e^{-x}}\left(\sqrt{\frac{2}{e^{x} + e^{-x}}} \cdot \sqrt{\sqrt{2}}\right) \cdot \sqrt{\frac{\sqrt{2}}{e^{x} + e^{-x}}}double f(double x) {
double r56439 = 2.0;
double r56440 = x;
double r56441 = exp(r56440);
double r56442 = -r56440;
double r56443 = exp(r56442);
double r56444 = r56441 + r56443;
double r56445 = r56439 / r56444;
return r56445;
}
double f(double x) {
double r56446 = 2.0;
double r56447 = x;
double r56448 = exp(r56447);
double r56449 = -r56447;
double r56450 = exp(r56449);
double r56451 = r56448 + r56450;
double r56452 = r56446 / r56451;
double r56453 = sqrt(r56452);
double r56454 = sqrt(r56446);
double r56455 = sqrt(r56454);
double r56456 = r56453 * r56455;
double r56457 = r56454 / r56451;
double r56458 = sqrt(r56457);
double r56459 = r56456 * r56458;
return r56459;
}



Bits error versus x
Results
Initial program 0.0
rmApplied add-sqr-sqrt0.0
rmApplied *-un-lft-identity0.0
Applied add-sqr-sqrt0.0
Applied times-frac0.0
Applied sqrt-prod0.0
Applied associate-*r*0.0
Simplified0.0
Final simplification0.0
herbie shell --seed 2019323 +o rules:numerics
(FPCore (x)
:name "Hyperbolic secant"
:precision binary64
(/ 2 (+ (exp x) (exp (- x)))))