\[ r \cdot \frac{\sin b}{\cos \left(a + b\right)}
\]
+-commutative [=>]76.6
\[ r \cdot \frac{\sin b}{\cos \color{blue}{\left(b + a\right)}}
\]
Applied egg-rr99.5%
\[\leadsto r \cdot \frac{\sin b}{\color{blue}{\mathsf{fma}\left(\cos b, \cos a, -\sin b \cdot \sin a\right)}}
\]
Applied egg-rr99.5%
\[\leadsto r \cdot \frac{\sin b}{\mathsf{fma}\left(\cos b, \cos a, -\color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\sin b \cdot \sin a\right)\right)}\right)}
\]
Final simplification99.5%
\[\leadsto r \cdot \frac{\sin b}{\mathsf{fma}\left(\cos b, \cos a, -\mathsf{expm1}\left(\mathsf{log1p}\left(\sin b \cdot \sin a\right)\right)\right)}
\]
Alternatives
Alternative 1
Accuracy
99.5%
Cost
39040
\[r \cdot \frac{\sin b}{\mathsf{fma}\left(\cos b, \cos a, \sin b \cdot \left(-\sin a\right)\right)}
\]
Alternative 2
Accuracy
99.5%
Cost
32704
\[r \cdot \frac{\sin b}{\cos b \cdot \cos a - \sin b \cdot \sin a}
\]
Alternative 3
Accuracy
99.4%
Cost
32512
\[\frac{r}{\mathsf{fma}\left(\frac{\cos b}{\sin b}, \cos a, -\sin a\right)}
\]