I know that this is an integral problem, but I'm stuck on some algebra within it. I'm doing a u-substitution on this problem:

So far, so good. Here's where I am stuck. According to Wolfram Alpha, when I do my u-substitution, I should get:

The denominator and the constant are obvious, but I can't see how they get from to in the numerator. Can somebody show this to me? Clearly I have a hole in my algebra abilities.

Thanks.