1. The problem statement, all variables and given/known data We are given Z, and are asked to find the magnitude of the expression. See attached picture(s) 2. Relevant equations See attached pictures(s) 3. The attempt at a solution When I solved it on the exam, I did it the long way using De Moivre's theorem. I ended up making a few sign errors which cost me points. When my professor went over the exam, he did the problem as shown on the second picture with the purple pen writing. What I am wondering is why you can solve it this way? Why in the denominator you can just multiple the magnitude of both terms without having to evaluate it?