Can someone please explain to me the sense in teaching quantum mechanics before lagrangian and hamiltonian mechanics? While in undergrad I took a course in intermediate mechanics which was from the first couple of chapters of marion and thornton - like 1-4 or something like that. Then I took qm for an entire semester before taking advanced dynamics where we briefly discussed lagrangian and hamiltonian formalisms. Now this is not because I chose to do this - the classes are setup as such. QM 1 is offered fall and then QM2 is offered spring concurrently with Advanced dynamics. Now I'm taking the graduate QM class and the graduate students in my class are just now, this late in the semester, being exposed to the beginnings of the lagrangian formalism in their mechanics class. I sat in the other day and they were doing the pendulum problem. I wager this is not unique to my school. The entire time I've been learning QM I'm constantly questioning things whose motivations come hamiltonian and lagrangian mechanics. I bet most other students are as well. Anyone have some opinions?