1. The problem statement, all variables and given/known data Hello! The problem is the one I attached. 2. Relevant equations 3. The attempt at a solution They say the answer is A, but I am not sure why. From what I remember from lab class, when you put 2 signals on x and y axis you get usually a closed loop, like D or E. I think D happens when you have the same frequency but different amplitudes so I assumed the answer is E. Can someone explain why is it A? Thank you.