A fundamental calculus operator representing indefinite or definite integration of functions over specified domains.
Examples
Basic definite integral
\int_0^1 x^2 dx = \frac{1}{3}
Indefinite integral with constant of integration
\int x^n dx = \frac{x^{n+1}}{n+1} + C
Double integral over a region
\int\int_D (x^2 + y^2) \,dy\,dx