You will be able to evaluate a definite integral by writing it as a limit of a Riemann sum
In this introductory video, we review the definition of a the area of a region in the plane as defined by a function and the x-axis. Recall that the area is defined as the limit of a Riemann sum, assuming the function in question is continuous and nonnegative. I wonder what happens when at least one of those conditions is violated... Duration: 3:50
On Example 1, let's take a look at what happens to the limit of a Riemann sum when part of the function dips down below the x-axis. Duration: 13:24