Ok I figured out #8, anyone want to help me out with the other?
I've attached a picture with two more problems I'm working on. For the first I have no idea what to use as u because it seems differentiating any term won't give you part of another term in the problem.
As for the second one, the fact that there's a dt in the numerator is throwing me off and I don't know what to do in problems like this.