Now we just have to evaluate this definite integral. Let's give a shot at it. This is going to be equal to the integral from 1 to 4, and we can factor out, or we can put the pi outside the integral sign, and then we can expand this out. Square root of x squared. All we're going to do is expand this binomial. Square root of x minus 1 times square root of x minus 1. Square root of x times square root of x is x.