# Integral question

1. Jan 15, 2009

### evilq17

I am having problems figuring out how to do this integral.
$$\int$$x(x2-4)1/2dx

I know what the answer is, but I am not sure how to get there. I am not sure if there is a method or if you just need to do it by logic. I tried integration by parts but I just cant get to something I can integrate.

Thanks.

2. Jan 15, 2009

### mathman

try y=x2-4. Then dy=2xdx. Now you are left with integrating (y1/2)/2. You should be able to do that.

3. Jan 15, 2009

### NoMoreExams

You probably COULD do it by parts? But that's clearly overkill. Like mathman pointed out, this screams u-subst.

4. Jan 15, 2009

### evilq17

Thanks. U substitution. Its been too long since I have done this. Thanks.