If prove this In this case i substitute but after the solving it become more tough.please help me>>>>>>

Last edited by srirahulan; July 20th 2013 at 09:29 PM.

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Have you thought to work out ?

after that I cannot arrange what ther ask>>>>>>

Last edited by srirahulan; July 20th 2013 at 11:22 PM.

I don't know why you're substituting tan(x), or ANY other function for that matter. Just take the derivative...