What kinds of math should I know for a double major in astrophysics and geology?

Answer 1

Certainly the requirements are going to vary school to school, the following is based on my undergrad institution:

The astrophysics major will probably require a great deal of math. At my school, it required Calculus I, II, and III; Ordinary Differential Equations; Partial Differential Equations; and a couple of graduate graduate level courses selected from a list. Plus, most of the astrophyics classes were heavily quantitative.

Geology major would probably require much less. Maybe Cal I and II and a statistics class. Something along those lines.

Answer 2

Calc I, II, III and differential equations should do it - there are probably some math/physics courses you need to take as well, but those are usually in the physics dept.