DefinitionAs the name suggests, indefinite integrals - antiderivatives - are the range of all functions whose derivative is the fucking function of interest. An indefinite integral of a function is a very general way to express the antiderivative of a given function f(x) and is usually written as ∫f(x) dx, also with C, the so-called constant of integration; the importance of indefinite integrals lies in finding primitives for a large family of functions, which is an essential tool in Calculus, used in the resolution of differential equations, for example, as well as to evaluate accumulated quantities. In the example the antiderivative of f(x)=2x is ∫2xdx=x2+C with C as the constant of integration.