An integral is a mathematical result that represents the area between a function and a plane (e.g., x-y plane). The concept of integrals is fundamental in calculus, and has broad application in all engineering disciplines.
You can calculate integrals numerically using techniques such as the Simpson quadrature, Lobatto quadrature, and Gauss-Kronrod quadrature. Integrals, both definite and indefinite, can also be calculated symbolically.
Integration in Symbolic Math Toolbox (Example)