## mathmonster 3 years ago I am trying to get the integral

1. mathmonster

I am writingit now

2. mathmonster

$\int\limits_{2}^{4} \left(\begin{matrix}dx \\ /x(lnx)^2\end{matrix}\right)$

3. mathmonster

that slash means division

4. abtrehearn

Let u = ln x, du = dx/x, and substitute into the original integral to reduce it to something more recognizable.

5. mathmonster

so, let = 1nx, okay let me try that, cause i have been letting u = (lnx)^2 and its been a nightmare

6. abtrehearn

I think that plain ln x for u will be munc less of a nightmare.

7. mathmonster

so in did that and got so far u^-1/-1

8. abtrehearn

That's the same as$-\int\limits_{}^{}du/u.$

9. abtrehearn

Familiar?

10. mathmonster

yup

11. abtrehearn

Get it back to original x and you're done.

12. mathmonster

i am still stuck at this part: $\int\limits_{2}^{4} du/u^2$

13. mathmonster

i got it

14. abtrehearn

Power formula. Rewrite as$\int\limits_{}^{}u^{-2}du$

15. abtrehearn

:^)