This reminds me of my father. He was a Physics Prof. and for 20'ish years in his Mathematical Methods class, he would always give the same problem as the first question on the first mid-term. "Write del^2 in spherical polar coordinates."

All of his past exams were on file in the Library.
He would tell the class that that was going to be the first question.
Every year, someone would get the question very wrong (as opposed to mistaken memory).

Listening in class is the best way to get a good grade. Besides, knowledge is the goal of the class, not a grade.