Hey all, I am currently a freshman double majoring in Physics and Math at Purdue University. I have been recently creating a schedule that orders all of the courses I need to take and those that I want to take for the rest of my undergraduate endeavors. I know that it's rather early to do this, but I need to. If I craft my schedule in a certain way quite soon, I may able to avoid taking classes this summer, graduate in four year, and most importantly, save money. I love physics and math; so if I feel as though that there is a course I need to enroll in, I will do so unquestionably. So here is the question: what are the most important undergraduate math courses for a student who wishes to focus on theoretical physics and go to graduate school for a PhD? (I know that Linear Algebra is considered quite important, but I would much appreciate it if you can list more than one. Perhaps five or six?) I would love to hear your lists. Thanks a bunch.