2 \cdot \tan^{-1} \left(\sqrt{\frac{1 - x}{1 + x}}\right)2 \cdot \tan^{-1} \left(\frac{\sqrt{1 - x}}{\sqrt{1 + x}}\right)double f(double x) {
double r604889 = 2.0;
double r604890 = 1.0;
double r604891 = x;
double r604892 = r604890 - r604891;
double r604893 = r604890 + r604891;
double r604894 = r604892 / r604893;
double r604895 = sqrt(r604894);
double r604896 = atan(r604895);
double r604897 = r604889 * r604896;
return r604897;
}
double f(double x) {
double r604898 = 2.0;
double r604899 = 1.0;
double r604900 = x;
double r604901 = r604899 - r604900;
double r604902 = sqrt(r604901);
double r604903 = r604899 + r604900;
double r604904 = sqrt(r604903);
double r604905 = r604902 / r604904;
double r604906 = atan(r604905);
double r604907 = r604898 * r604906;
return r604907;
}



Bits error versus x
Results
Initial program 0.0
rmApplied sqrt-div0.0
Final simplification0.0
herbie shell --seed 2019172
(FPCore (x)
:name "arccos"
(* 2.0 (atan (sqrt (/ (- 1.0 x) (+ 1.0 x))))))