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Trignometry

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16 Aug 2009 13:47:01 IST

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if cos(a-b)/cos(a+b) +cos(c+d)/cos(c-d)=0prove thattana.tanb.tanc.tand= -1

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if cos(a-b)/cos(a+b) +cos(c+d)/cos(c-d)=0prove thattana.tanb.tanc.tand= -1

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Akshay

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Joined: 1 Aug 2009

Posts: 101

16 Aug 2009 14:34:12 IST

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cos(a-b)/cos(a+b)= - cos(c+d)/cos(c-d)

apply componendo dividendo.......(cos(a-b)-cos(a+b))/((cos(a-b)+cos(a+b)) = (-cos(c+d)-cos(c-d))/(-cos(c+d)+cos(c-d))

tame minus commen from RHS and aplly cosine identity

Soumen Goswami

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Joined: 10 Apr 2007

Posts: 1777

16 Aug 2009 23:08:57 IST

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