Before we formally define the definite integral, we have to understand the norm, which is basically the barfly of the subintervals used as the width of our rectangles. Duration: 7:12

Now that we have the definition of a definite integral down, let's evaluate one on Example 2 by, of course, rewriting it as a limit of a Riemann sum. Duration: 8:51

We know how do identify a differentiable function, but how do we identify an integrable function? It's certainly easier than you think. Also, let's get some worry-free practice at writing the limit of a Riemann sum as a definite integral, as I have it on good authority that's what you'll have to do on the AP Exam. Duration: 12:46