2 \cdot \tan^{-1} \left(\sqrt{\frac{1 - x}{1 + x}}\right)\tan^{-1} \left(\sqrt{\frac{1 - x}{1 + x}}\right) \cdot 2double f(double x) {
double r214724 = 2.0;
double r214725 = 1.0;
double r214726 = x;
double r214727 = r214725 - r214726;
double r214728 = r214725 + r214726;
double r214729 = r214727 / r214728;
double r214730 = sqrt(r214729);
double r214731 = atan(r214730);
double r214732 = r214724 * r214731;
return r214732;
}
double f(double x) {
double r214733 = 1.0;
double r214734 = x;
double r214735 = r214733 - r214734;
double r214736 = r214733 + r214734;
double r214737 = r214735 / r214736;
double r214738 = sqrt(r214737);
double r214739 = atan(r214738);
double r214740 = 2.0;
double r214741 = r214739 * r214740;
return r214741;
}



Bits error versus x
Results
Initial program 0.0
Final simplification0.0
herbie shell --seed 2019142
(FPCore (x)
:name "arccos"
(* 2 (atan (sqrt (/ (- 1 x) (+ 1 x))))))