\frac{\cos^{-1} \left(\frac{x - 1}{2}\right)}{2 \cdot \sin \left(\cos^{-1} \left(\frac{x - 1}{2}\right)\right)}\frac{\cos^{-1} \left(\frac{x - 1}{2}\right)}{2 \cdot \sin \left(\cos^{-1} \left(\frac{x - 1}{2}\right)\right)}double code(double x) {
return ((double) (((double) acos(((double) (((double) (x - 1.0)) / 2.0)))) / ((double) (2.0 * ((double) sin(((double) acos(((double) (((double) (x - 1.0)) / 2.0))))))))));
}
double code(double x) {
return ((double) (((double) acos(((double) (((double) (x - 1.0)) / 2.0)))) / ((double) (2.0 * ((double) sin(((double) acos(((double) (((double) (x - 1.0)) / 2.0))))))))));
}



Bits error versus x
Results
Initial program 1.5
Final simplification1.5
herbie shell --seed 2020153
(FPCore (x)
:name "(/ (acos (/ (- x 1) 2)) (* 2 (sin (acos (/ (- x 1) 2)))))"
:precision binary64
(/ (acos (/ (- x 1.0) 2.0)) (* 2.0 (sin (acos (/ (- x 1.0) 2.0))))))