## Precalculus (6th Edition) Blitzer

$\frac{{{r}_{1}}\left( \cos {{\theta }_{1}}+i\sin {{\theta }_{1}} \right)}{{{r}_{2}}\left( \cos {{\theta }_{2}}+i\sin {{\theta }_{2}} \right)}=\frac{{{r}_{1}}}{{{r}_{2}}}\left[ \cos \left( {{\theta }_{1}}-{{\theta }_{2}} \right)+i\sin \left( {{\theta }_{1}}-{{\theta }_{2}} \right) \right]$. The quotient of two complex numbers in polar form is found by dividing their moduli and subtracting their arguments.