SOLUTION: Can you help me solve this trigonometric identities question: 1)Prove each of the following identities. a)cos^2 x +2sin^2 x -1=sin^2 x

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Question 204685: Can you help me solve this trigonometric identities question: 1)Prove each of the following identities.
a)cos^2 x +2sin^2 x -1=sin^2 x
Answer by HyperBrain(694) About Me  (Show Source):
You can put this solution on YOUR website!

But, sin%5E2%28x%29%2Bcos%5E2%28x%29=1. So
cos%5E2+%28x%29+%2B+sin%5E2+%28x%29%2B+sin%5E2+%28x%29+-+1=1+%2B+sin%5E2%28x%29+-+1
=sin%5E2%28x%29+%2B+1+-1
=sin%5E2%28x%29