1. The problem statement, all variables and given/known data The problem at hand is that I don't understand wherefrom my text book got a certain term(e^(2*pi*i). It doesn't say. At least not as I understand it. The book says: 2. Relevant equations e^(z+2*pi*i) = e^z*e^(2*pi*i) = e^z*1 = e^z From where does e^(2*pi*i) come? I get the stuff leading to the answer, I just can't seem to understand from where that term comes from.