Fubini's Theorem

Fubini's Theorem is a fundamental result in calculus that allows us to evaluate complex double integrals—integrals over two variables—by breaking them into simpler, single-variable integrals. Essentially, it states that if a function meets certain conditions, you can integrate it first with respect to one variable and then with respect to the other, and the order of integration doesn't change the result. This provides flexibility and simplifies calculations, especially in multidimensional problems, making it easier to analyze functions across areas or volumes.