Quote by Bogrune
At the moment, my first choice for a major is in Economics, and after doing some research, I've found out that the mathematics courses required for a PhD are Probability and Statistics, SingleVariable Calculus (Calc. 1 and 2), Multivariable Calculus, Linear Algebra and both Ordinary and Partial Differential Equations. My question is: What is required for preparation for Differential Equations? Also, are Partial Differential Equations really as difficult as most people say they are (which they is are very difficult)?

You need Calc II and Linear Algebra for ordinary differential equations, pde's will require those and multivariable calculus; it can be very difficult depending on the professor and whether he cares or not that you can finish your exams on time.