## anonymous 5 years ago How do I show that I know the integral of ln(x)?

1. anonymous

$\int\limits_{a}\ln(x){b} = ?$

2. anonymous

Do it by parts.

3. anonymous

And how do I do that?

4. anonymous

u=lnx dv=dx du=dx v=x

5. anonymous

Do you know what integration by parts is?

6. anonymous

I think I do, but I cant recognize the term.

7. anonymous

sorry, du=1/x dx

8. anonymous

$\int\limits v\frac{\mathbb{d}u}{\mathbb{d}x} = uv + \int\limits u\frac{\mathbb{d}v}{\mathbb{d}x}$ Where u and v are functions of x.

9. anonymous

Both of those integrations are with respect to x, I neglected to mention!

10. anonymous

You're going to need to get comfortable with the integration by parts formula, as INewton posted above. Review this section in your book until it, along with the parts I posted above, make sense.