Here is my situation, I am a physics major who is also minoring in math. I have already taken Calc1-3 and Diff EQ as well as an intro to linear algebra course. I am scheduled to take a vector analysis course this Fall. The reason for my choice of linear algebra and vector analysis is because they are both pre-requisites for differential geometry which I was told by my advisor as being a good course to take as a physics major. I recently had an appointment with the math department to certify my math minor outline for the Post 9/11 GI bill. I was told by my math advisor that differential geometry has not been taught in a very long time and I shouldn't cross my fingers that it will be taught this upcoming spring. I am still going to take vector analysis because I was told it is still a good math class to have under my belt. So, after this semester I will have one more math class to fulfill my minor requirement. I was hoping to get the recommendation of the members on this forum as to which upper division math class I should take. My choices are below followed with their catalog description: Complex Variables: A first course in complex function theory, with emphasis on applications Fourier Series and Boundary Value Problems: Fourier series and methods of solution of the boundary value problems of applied mathematics Calculus of Variations and Optimal Control: Euler's equations, conditions for extrema, direct methods, dynamic programming, and the Pontryagin maximal principle These three upper division classes are really the only options for me based on pre-requisites. So which of these classes do you think would be a good option for me as a physics major? Thanks for any input in advance.