This article mainly introduces the application of definite integrals. There are four parts in this article, and each part corresponds to an example. The first part is calculation of definite integrals area of plane images. In the first part, two methods are used in one stop to provide different solutions to definite integrals in different questions. The second part is using define integration to calculate the volume of regular-shaped solid. This part explains the general formula used in childhood. The third part is definite integral to calculate the volume of a rotation solid, which explains how to use definite integrals to calculate the volume under the condition of only one coordinate system. The fourth part is using defined integration to solve kinematics problems., which describes the use of definite integrals in other subjects. Calculus not only provides precise mathematical descriptions and solving methods for physics, but also promotes the development and progress of various fields of physics.
