# Thread: Integration by parts

1. ## Integration by parts

The question:
Use integration by parts to evaluate the following integral

$\int ln(x) dx$

I'm not sure what to do, since this looks like a single part to me. I'm clearly missing something fundamental here. Thanks.

2. The general form is

$\int u \, dv = u v - \int v \, du$

Let $u=\ln x$ and $dv=dx$. What does this give you?

Notice that if you work this problem this way, you do not have to know what the integral of $\ln x$ is! Instead you only need to know the derivative of $\ln x$ to compute $du$. That is the reason for using the method.

3. Thanks dude!