Answer
${{r}_{1}}\left( \cos {{\theta }_{1}}+i\sin {{\theta }_{1}} \right).{{r}_{2}}\left( \cos {{\theta }_{2}}+i\sin {{\theta }_{2}} \right)=$ ${{r}_{1}}{{r}_{2}}\left[ \cos \left( {{\theta }_{1}}+{{\theta }_{2}} \right)+i\sin \left( {{\theta }_{1}}+{{\theta }_{2}} \right) \right]$.
The product of two complex numbers in polar form is found by multiplying their moduli and adding their arguments.
Work Step by Step
Given above.
