\frac{r \cdot \sin b}{\cos \left(a + b\right)}\frac{r}{\cos a \cdot \cos b - \sin a \cdot \sin b} \cdot \sin bdouble code(double r, double a, double b) {
return ((r * sin(b)) / cos((a + b)));
}
double code(double r, double a, double b) {
return ((r / ((cos(a) * cos(b)) - (sin(a) * sin(b)))) * sin(b));
}



Bits error versus r



Bits error versus a



Bits error versus b
Results
Initial program 14.0
rmApplied cos-sum0.3
rmApplied associate-/l*0.4
rmApplied associate-/r/0.3
Final simplification0.3
herbie shell --seed 2020066
(FPCore (r a b)
:name "r*sin(b)/cos(a+b), A"
:precision binary64
(/ (* r (sin b)) (cos (+ a b))))