uestion Consider the multiplicative group C* of complex numbers, n e N, and a subset Un := {z C| 2" = 1}. (a) Show that U, is a subgroup of C*. (b) For w = cos()+ i sin(), show that (w) = Un. (c) Show that the order of Un is n. (Hint: show that for k EN such that k < n, wk + 1).