Pre calc help please!!!

Question

Use DeMoivre’s Theorem to find the following

Answer 1

3(cis 10π)

10π is coterminal with 0

3(cis 0) = ?

Answer 2

DeMoivre's Theorem states that, if n is an integer and x is a real number, then (cis(x))^n = cis(nx) = cos(nx)+i sin(nx). So, in the case of your problem, can you identify what n and x might be? Once you figure that out, then you can multiply n*x and that becomes the new argument of cis(). The 3 out front in your problem means that we need to multiply cis(nx) by 3 to get our final answer.