\[r \cdot \frac{\sin b}{\color{red}{\cos \left(a + b\right)}} \leadsto r \cdot \frac{\sin b}{\color{blue}{\cos a \cdot \cos b - \sin a \cdot \sin b}}\]
0.3
Using strategy rm
0.3
Applied clear-num to get
\[r \cdot \color{red}{\frac{\sin b}{\cos a \cdot \cos b - \sin a \cdot \sin b}} \leadsto r \cdot \color{blue}{\frac{1}{\frac{\cos a \cdot \cos b - \sin a \cdot \sin b}{\sin b}}}\]
0.4
Applied simplify to get
\[r \cdot \frac{1}{\color{red}{\frac{\cos a \cdot \cos b - \sin a \cdot \sin b}{\sin b}}} \leadsto r \cdot \frac{1}{\color{blue}{\frac{\cos a}{\frac{\sin b}{\cos b}} - \sin a}}\]
0.4
Removed slow pow expressions
Original test:
(lambda ((r default) (a default) (b default))
#:name "r*sin(b)/cos(a+b), B"
(* r (/ (sin b) (cos (+ a b)))))