I have a question about one of the questions on the 1992 Physics GRE. Some fellow students and I and a professor are going over questions to prepare for the PGRE and we came across one question that we can't seem to get a hang of. http://grephysics.net/ans/9277/17 This is the question with a supposed answer which we don't buy and there seems to be a lot of argument over the actual solutions. The solution on the site and what we suppose is ETS's claim (since they say the answer is A as well) is that the oscilloscope is graphing Voltage vs. Time and that the function is basically y(t) = Sin(t) + Sin(2t) and that the answer represents one of the large humps in the function. However, me and my fellow students seem to have come to an agreement that the oscilloscope must be in X-Y mode (and not Y vs. t or however one woudl construe the question to be) and what you would get would be what is apparently called a Lissajous Curve. Now (E) is such a curve but with the ratio of frequencies in reverse (The X is twice the frequency as Y). What does everyone think about this? In no way does the question seem to assert that the X-axis is infact, time.