Reversing the Bounds of a Definite Integral - Expii
We've seen how to define a definite integral on an interval when a≤b (so that [a,b] is an interval), but there is also a convenient definition we can make when the endpoints are "backwards". Specifically, when a>b, you can interpret the integral from a to b as the negative of the usual integral from b to a. This definition allows you to generalize the additive interval property to allow a,b,c to be any real numbers, not necessarily with a≤b≤c. All of this will be convenient when discussing integral functions and FTC later on.