SOLUTION: Prove: Cos^4(x) - Sin^4(x) = 1 - 2Sin^2(x) Thank you

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Question 927209: Prove:
Cos^4(x) - Sin^4(x) = 1 - 2Sin^2(x)
Thank you
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Prove:
Cos^4(x) - Sin^4(x) = 1 - 2Sin^2(x)
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(cos^2)^2 - (sin^2)^2 = 1 - 2sin^2
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(1-sin^2)^2 - (sin^2)^2 + 2sin^2 = 1
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1 - 2sin^2 + sin^4 -sin^4 + 2sin^2 = 1
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1 = 1
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Cheers,
Stan H.
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