Expii

Multiplying and Dividing Complex Numbers in Polar Form - Expii

It turns out to be super easy to multiply complex numbers in polar form. Just multiply the magnitudes r, and add the angles, using the fact that (cos(x) + i sin(x)) (cos(y) + i sin(y)) = cos(x+y) + i sin(x+y). BTW, this is a great way to remember the angle addition identities.