For the transformation show that as z moves once round the circle centre O and radius 2, w moves twice round the circle center O and radius 4.

I have two problems for which I am stuck on the sum:

1. How do moving "once" and "twice" is represented on the equation? That is, if w lies on circle center O and radius 4, , but how do show that it movestwice?

2. If i take : how do I do this part: , when w is a complex number?

And how do i carry out from there :help: