Calculus

Integral calculus is the study of integration and methods for evaluating integrals. Integrals come in two kinds, definite and indefinite. The definite integral of a function, interpreted geometrically, corresponds to the area under the curve of the function between any two Figure 2. Consider approximating the area under the graph of a function f(x) by drawing a series of rectangles, and summing their areas to arrive at the total area. Illustration by Hans & Cassidy. Courtesy of Gale Group. limits. Thus, it has a definite value depending on the limits chosen, The indefinite integral of a function is the inverse of the derivative of that function. That is, integrating (finding the integral) undoes differentiating (finding the derivative f'(x)). Integrating the derivative of a function returns the original function.