I was working on a basic problem (a little single-variable calc), and it seems my answer differs from the one my text provides.

The above is what my text says the answer is. Here's my work:

It doesn't seem my answer is equivalent to the text's, so either I did a mistake or the text is wrong. In fact, all that seems to differ is the factor of . Can someone shed a little light here? Much appreciated.

We'll make a substitution:

From our substitution, we know , giving

Integrate by parts: and

Substituting back in, we get