Question

does anyoe know how to find the integral of (ln x )^2

Answer 1

You should set ln(x) = u

Answer 2

Then du=dx/x

Answer 3

But x=e^u from the definition of u.

Answer 4

So dx=e^(-u)du

Answer 5

You then use integration by parts a couple of times.

Answer 6

Since the integrand is u^2e^(-u), pick on the u^2 as the part in IBP that you differentiate. When you repeat the process, eventually the derivative will be zero, and you'll be done.

Answer 7

Learn 'tabular integration by parts'

http://en.wikipedia.org/wiki/Integration_by_parts

You will be able to punch these out in a flash.