A definite integral is an integral whose variables are limited in a certain range, and it has a range. Calculus includes differential and integral, which are reciprocal operations. Integral includes definite integral and indefinite integral, and indefinite integral has no range.

As we all know, the two major parts of calculus are differential and integral. In the case of unary function, differentiation is actually the derivative function of the known function, and integration is the original function of the known derivative function. So differential and integral are reciprocal operations.

Calculus is a branch of mathematics, which studies the differential and integral of functions and related concepts and applications in higher mathematics. It is the basic subject of mathematics. The content mainly includes limit, differential calculus, integral calculus and its application. Differential calculus, including the calculation of derivatives, is a set of theories about the rate of change. It makes the function, velocity, acceleration and curve slope can be discussed with a set of universal symbols. Integral calculus, including the calculation of integral, provides a set of general methods for defining and calculating area and volume.