SOLUTION: verify the identity cos2x=(cot^2 x-1)/cot^2 x+1

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Question 679413: verify the identity
cos2x=(cot^2 x-1)/cot^2 x+1
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
verify the identity
cos2x=(cot^2 x-1)/cot^2 x+1
start with right side
(cot^2x-1)/cot^2x+1
[(cos^2x/sin^2x)-1]/[(cos^2x/sin^2x)+1]
=[(cos^2x-sin^2x)/sin^2x]/[(cos^2x+sin^2x)/sin^2x]
sin^2x cancels out
=[(cos^2x-sin^2x)/[(cos^2x+sin^2x)]
=[(cos^2x-sin^2x)/1
=cos2x
verified: right side=left side