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 r242962 = 2.0;
double r242963 = 1.0;
double r242964 = x;
double r242965 = r242963 - r242964;
double r242966 = r242963 + r242964;
double r242967 = r242965 / r242966;
double r242968 = sqrt(r242967);
double r242969 = atan(r242968);
double r242970 = r242962 * r242969;
return r242970;
}
double f(double x) {
double r242971 = 1.0;
double r242972 = x;
double r242973 = r242971 - r242972;
double r242974 = r242971 + r242972;
double r242975 = r242973 / r242974;
double r242976 = sqrt(r242975);
double r242977 = atan(r242976);
double r242978 = 2.0;
double r242979 = r242977 * r242978;
return r242979;
}



Bits error versus x
Results
Initial program 0.0
Final simplification0.0
herbie shell --seed 2019152
(FPCore (x)
:name "arccos"
(* 2 (atan (sqrt (/ (- 1 x) (+ 1 x))))))