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(calculus) The calculus that generalizes summation to find areas, masses, volumes, sums, and totals of quantities described by continuously varying functions.

A definite integral of a function can be represented as the signed area of the region bounded by its graph and the horizontal axis; in the above graph as an example, the integral of ${\displaystyle f(x)}$ is the yellow (−) area subtracted from the blue (+) area

(calculus) The calculus that generalizes summation to find areas, masses, volumes, sums, and totals of quantities described by continuously varying functions.

Approximations to integral of √x from 0 to 1, with 5 yellow right endpoint partitions and 10 green left endpoint partitions

(calculus) The calculus that generalizes summation to find areas, masses, volumes, sums, and totals of quantities described by continuously varying functions.

Darboux upper sums of the function y = x²