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Trignometry

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11 Jan 2012 12:23:02 IST

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How to prove that

Mathematics

Prove that Cos(pi+x) cos(-x)/sin(pi-x) cos(pi/2+x)=cot^2x

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sirisha

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Joined: 19 Dec 2011

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11 Jan 2012 18:23:21 IST

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-cosx*cosx/-sinxcosx=cos^2x/sinxcosx=multiply n divide by 2

=2cos^2x/2sinxcosx

=2cos^2x/sin2x

=2cos^2x-1/sin2x

=cos2x/sin2x =cot2x

Abhishek Das

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Joined: 16 Aug 2011

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11 Jan 2012 19:24:56 IST

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lol...at sirisha how cos(pi/2+x)=-cosx???

sidharthsekharsahoo

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Joined: 9 Jan 2012

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11 Jan 2012 20:00:18 IST

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it is to prove cot square x u have proved cot2x

sirisha

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Joined: 19 Dec 2011

Posts: 79

11 Jan 2012 21:06:22 IST

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sry its a mistake -cosxcosx/-sinxsinx=cot^2x

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