# INtegration by substitution followed by parts:

... of (x tan^2 x). i dunno how to do it. pls help

cristo
Staff Emeritus
Well, what have you tried? This is clearly homework! Try writing tanx in terms of sinx and cosx.

i tried that. i even tried using trig identities for the expansion of tan^2 but i got no where. im lost...

any ideas?

this is by-parts integration because you have two functions multiplied by each other.
But before you do that you should use a trig identity (think of an identity which will give you an easily integratable trig function).

Gib Z
Homework Helper
Good work though :P

cristo
Staff Emeritus