a function ф(x) is called a primitive or an antiderivative of a function f(x) if ф'(x) = f(x).
For a function f(x), the collection of all its primitives is called the indefinite integral of f(x0 and is denoted by ∫f(x)dx.
∫f(x)dx = ф(x)+C (where C is a constant)
Here ∫ is the integral sign, f(x) is th integrand, x is the variable of integration and dx is the element of integration or differential of x.
The process of finding an indefinite integral of a given function is called integration of the function.