# Math Help - Integration by trig substitutions.

1. ## Integration by trig substitutions.

Edit: stupid mistake. I didn't have anything wrong to begin with.

2. Just substitute $x = 3\sin{\theta}$

then $dx = 3\cos{\theta}d\theta$

You should end up at $\int \cot^2{\theta} d\theta$

3. That's... exactly where I am now. My substitutions were different than yours, but they give the same exact problem.