Initial program 14.9
\[r \cdot \frac{\sin b}{\cos \left(a + b\right)}\]
- Using strategy
rm Applied cos-sum0.3
\[\leadsto r \cdot \frac{\sin b}{\color{blue}{\cos a \cdot \cos b - \sin a \cdot \sin b}}\]
- Using strategy
rm Applied *-un-lft-identity0.3
\[\leadsto r \cdot \frac{\color{blue}{1 \cdot \sin b}}{\cos a \cdot \cos b - \sin a \cdot \sin b}\]
Applied associate-/l*0.4
\[\leadsto r \cdot \color{blue}{\frac{1}{\frac{\cos a \cdot \cos b - \sin a \cdot \sin b}{\sin b}}}\]
Taylor expanded around -inf 0.4
\[\leadsto r \cdot \frac{1}{\color{blue}{\frac{\cos a \cdot \cos b - \sin a \cdot \sin b}{\sin b}}}\]
Simplified0.4
\[\leadsto r \cdot \frac{1}{\color{blue}{\frac{\cos a}{\frac{\sin b}{\cos b}} - \sin a}}\]
- Using strategy
rm Applied quot-tan0.4
\[\leadsto r \cdot \frac{1}{\frac{\cos a}{\color{blue}{\tan b}} - \sin a}\]
Final simplification0.4
\[\leadsto \frac{1}{\frac{\cos a}{\tan b} - \sin a} \cdot r\]