Quote Originally Posted by AbysmalGuilt View Post
Someone want to help meh out? I have two probs, I know some of you are math wizzes from reading the last math thread.

Anyways, problem:

Evaluate the integral. Solve by the simplest method--not all require integration by parts. (I don't know how to make the integral sign so you'll have to assume it's there.)

(x^4)(lnx)dx

and

1/x(lnx)^3 dx


First problem, toughest thing is, since I'm trying to make lnx my dv, I dunno how to integrate lnx. I looked this up and it said make lnx my u since it's easier to find the derivative for it (which it is) however, it never comes to a 0...

Suggestions please. You don't have to answer it for me, but any hints will work. Thanks much.
Ok, so the second one is really [(1/x)(ln|x|)^3]dx, and you want to integrate. Well, first hand I'll give ya the derivative of ln|x|, which is 1/x. And the derivate you're given has 1/x in it, so it has to come from somewhere. Hope this gives you a big enough hint.

Edit: whoops! sorry if I'm confusin ya too much bud, been a long time. Here's the integration by parts rule:

Given an integral, we can treat it as the integral of f(x)g'(x)dx, which then we can then do f(x)g(x) - the integral of f'(x)g(x). Now, personally, here's what I'd do. You see that ln|x|? You can now do something with it and make this a whole lot nicer. Once again, sorry for the gibberish earlier, I needed to get my facts straight