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 r182191 = 2.0;
double r182192 = 1.0;
double r182193 = x;
double r182194 = r182192 - r182193;
double r182195 = r182192 + r182193;
double r182196 = r182194 / r182195;
double r182197 = sqrt(r182196);
double r182198 = atan(r182197);
double r182199 = r182191 * r182198;
return r182199;
}
double f(double x) {
double r182200 = 1.0;
double r182201 = x;
double r182202 = r182200 - r182201;
double r182203 = r182200 + r182201;
double r182204 = r182202 / r182203;
double r182205 = sqrt(r182204);
double r182206 = atan(r182205);
double r182207 = 2.0;
double r182208 = r182206 * r182207;
return r182208;
}



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