I have two classes that I think I can fit in on my last semester at university. I am doing the combined Mathematics & Physics major. I am more interested in physics. However, the two classes I can fit, happen to be mathematics classes. PDE's seem like they are very useful for physics and differential geometry excites me becuz it's the first class where I will learn the mathematics of General Relativity. What do you think? Or perhaps should I take electronics, atomic & nuclear physics, optics, topology I...etc.