\log \left(x + \sqrt{x \cdot x - 1}\right)\log \left(\frac{\sqrt{x}}{\sqrt{\frac{1}{2}}} - \sqrt{\frac{\frac{\frac{1}{8}}{x}}{x \cdot x} + \frac{\frac{1}{2}}{x}}\right) + \log \left(\frac{\sqrt{x}}{\sqrt{\frac{1}{2}}} + \sqrt{\frac{\frac{\frac{1}{8}}{x}}{x \cdot x} + \frac{\frac{1}{2}}{x}}\right)double f(double x) {
double r2255505 = x;
double r2255506 = r2255505 * r2255505;
double r2255507 = 1.0;
double r2255508 = r2255506 - r2255507;
double r2255509 = sqrt(r2255508);
double r2255510 = r2255505 + r2255509;
double r2255511 = log(r2255510);
return r2255511;
}
double f(double x) {
double r2255512 = x;
double r2255513 = sqrt(r2255512);
double r2255514 = 0.5;
double r2255515 = sqrt(r2255514);
double r2255516 = r2255513 / r2255515;
double r2255517 = 0.125;
double r2255518 = r2255517 / r2255512;
double r2255519 = r2255512 * r2255512;
double r2255520 = r2255518 / r2255519;
double r2255521 = r2255514 / r2255512;
double r2255522 = r2255520 + r2255521;
double r2255523 = sqrt(r2255522);
double r2255524 = r2255516 - r2255523;
double r2255525 = log(r2255524);
double r2255526 = r2255516 + r2255523;
double r2255527 = log(r2255526);
double r2255528 = r2255525 + r2255527;
return r2255528;
}



Bits error versus x
Results
Initial program 31.1
Taylor expanded around inf 0.3
Simplified0.3
rmApplied add-sqr-sqrt0.3
Applied add-sqr-sqrt0.3
Applied add-sqr-sqrt0.3
Applied times-frac0.3
Applied difference-of-squares0.3
Applied log-prod0.2
Final simplification0.2
herbie shell --seed 2019130
(FPCore (x)
:name "Hyperbolic arc-cosine"
(log (+ x (sqrt (- (* x x) 1)))))