\frac{r \cdot \sin b}{\cos \left(a + b\right)}\left(r \cdot \sin b\right) \cdot \frac{1}{\cos b \cdot \cos a - \sin a \cdot \sin b}double f(double r, double a, double b) {
double r15977 = r;
double r15978 = b;
double r15979 = sin(r15978);
double r15980 = r15977 * r15979;
double r15981 = a;
double r15982 = r15981 + r15978;
double r15983 = cos(r15982);
double r15984 = r15980 / r15983;
return r15984;
}
double f(double r, double a, double b) {
double r15985 = r;
double r15986 = b;
double r15987 = sin(r15986);
double r15988 = r15985 * r15987;
double r15989 = 1.0;
double r15990 = cos(r15986);
double r15991 = a;
double r15992 = cos(r15991);
double r15993 = r15990 * r15992;
double r15994 = sin(r15991);
double r15995 = r15994 * r15987;
double r15996 = r15993 - r15995;
double r15997 = r15989 / r15996;
double r15998 = r15988 * r15997;
return r15998;
}



Bits error versus r



Bits error versus a



Bits error versus b
Results
Initial program 15.0
rmApplied cos-sum0.3
rmApplied *-un-lft-identity0.3
Applied times-frac0.3
Simplified0.3
Simplified0.3
rmApplied div-inv0.4
Applied associate-*r*0.4
Final simplification0.4
herbie shell --seed 2019362
(FPCore (r a b)
:name "r*sin(b)/cos(a+b), A"
:precision binary64
(/ (* r (sin b)) (cos (+ a b))))