By integrating the difference of two functions, you can find the area between them.
We're used to finding the area under curves in the Cartesian plane, but integration can be used to find area defined by polar curves too.
Integral calculus isn't only useful for finding area. For example, it can also be used to find lengths of one-dimensional curves. Learn all about it here.
All video content by Khan Academy is under their license: CC by NC SA
Website created using Khan Academy Static Downloader