r \cdot \frac{\sin b}{\cos \left(a + b\right)}r \cdot \frac{1}{\frac{\cos a \cdot \cos b - \sin a \cdot \sin b}{\sin b}}double code(double r, double a, double b) {
return (r * (sin(b) / cos((a + b))));
}
double code(double r, double a, double b) {
return (r * (1.0 / (((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 15.0
rmApplied cos-sum0.3
rmApplied clear-num0.4
Final simplification0.4
herbie shell --seed 2020049
(FPCore (r a b)
:name "r*sin(b)/cos(a+b), B"
:precision binary64
(* r (/ (sin b) (cos (+ a b)))))