Basically, it's been 5 years since I went to college and I never took Calculus 2. I dropped out of Calculus 1 because the teacher was a foreign old man and he spoke broken english, most of the lectures I couldn't really understand what he was saying and he had a really aggressive attitude with no bedside manner so I always felt on edge and could never really focus or connect with him on any of his lectures. Basically, I don't want be overly harsh on the dude, but the dude had a 1.5/5 rating on ratemyprofessor. But I have been looking at this topic Spoiler: langrangians https://www.physicsforums.com/threads/lagrangian-differentiation.910585/#post-5736809 and it looks like something I could understand, just don't understand yet, if it was taught to me in a proper manner and not just thrown at me wikipedia style. Basically, the colleges around me suck and I also don't have much money, so I'm wondering what online courses or youtube series would be best for me to learn the stuff in order to learn lagrangians, then once I learn that (such as derivative equations and such) then what would be the best place to learn lagrangians. My second question is, is learning langrangians a waste of time, because the reason I want to learn the lagrangians is that there are some problems with the Newtonian model in-terms of game friction simulations. Basically, in real life, a tirewheel functions like a gear on a toothed rail, and Newtonian physics does not treat it like a gear on rail system, instead it treats it like a thrust force which it is not. So I am wondering if langrangians will help because wikipedia describes it as a replacement for the Newtonian model, and also mentions how it handles friction differently.