I am reading a passage of text that states:
"We can use the fact that $e^{a+bi}=e^a(\cos b+i\sin b)$ has polar form $\left
It then goes on to ask to express $e^z \times e^w$ in polar form where $z=a+bi$ and $w=c+di$.
Using the rule presented in the text above I can do this, what I am not clear on however is why this statement is true:
"We can use the fact that $e^{a+bi}=e^a(\cos b+i\sin b)$ has polar form $\left
I expect I am overlooking something here but I am not making much progress. I am not sure how the polar form in this general case has been derived.