Of course it's easy to understand. As long as you learn calculus and Newton Leibniz theorem well in high school. It's simple. That's what advanced mathematics is all about. Others include engineering mathematics, linear algebra and probability. Engineering mathematics needs high Fourier series and Euler formula, which is also very easy. The other two are also high school foundations, not to mention the probability. If you want to go deep into the field, you have to study mathematics.