... of (x tan^2 x). i dunno how to do it. pls help
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...
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).
Bruk, please read the PF guidelines here: https://www.physicsforums.com/showthread.php?t=5374, paying particular attention to the part re giving complete solutions to homework/textbook style questions.
Good work though :P
Hint: Do you know an identity for tan2x in terms of, say, sec2x?
Try using this then integrate by parts. Post your work so we can help you.
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