Who knows more mathematics: a regular physicist or an astrophysicist?

Do physicists use math? While physicists rely heavily on math for calculations in their work, they don't work towards a fundamental understanding of abstract mathematical ideas in the way that mathematicians do. Physicists want answers, and the way they get answers is by doing computations. Astrophysics is a branch of space science that applies the laws of physics and chemistry to seek to understand the universe and our place in it. You will need to know vector calculus, differential equations, and linear algebra (and of course all prerequisites). This is of course true of physics as well, and in fact the two require the same math.