Converting complex number raised to a power to polar form

Question

How would one convert $(1+i)^n$ to polar form?

I've heard about de Morgan's law but I don't know how to apply it here.

Answer 1

$$(1+i)^n=(\sqrt{2}e^{i\pi/4})^n=2^{n/2}e^{in\pi/4}=2^{n/2}[\cos(n\pi/4)+i\sin(n\pi/4)]$$