1. The problem statement, all variables and given/known data This is really a horizon broading, even music students and histroy students can take this course. So I think this HW problem is very simple, but it is too simple that I am afraid I will do it wrongly. 2. Relevant equations My Dr. said we don't need to know the C++ or any other cmputer language to do this question and he tell us to searh what is the meaning of "trace" in order to do this question. But I found it difficult to understand on the web(most of them contain computer language) 3. The attempt at a solution My thought is that, substitute n=4 into the 3 statements, then it's done. But it contain 10 marks!! So I better ask it.