How do I move on from the watered down maths I crammed before exams throughout undergrad, and onto more rigorous treatments? I'm one year into my engineering phd and I feel fucked but unwilling to admit it to my supervisor because I don't want to disappoint him further. Should I just start from the beginning with Spivak/Tenenbaum, do the exercises etc or is that a waste of time? Any resource for "kinda know the stuff"?