I have a B.S in Mathematics, but wish to pursue Theoretical Physics. I still have a great deal of undergraduate Physics coursework to take before I can apply to graduate programs. My question has to do with the Mathematics that is crucial in order to do Theoretical Physics. Is the mathematics within Physics courses self contained or should I study the advanced mathematics ("from a mathematicians perspective") that is used for Theoretical physics, separately? I haven't covered differential geometry or topology, so should I take these courses from the math department or should I just let the physics courses teach me the mathematics that I need to know in order to be a theoretical physicist?