SOLUTION: How do you prove that 1-cos2x=2sin^2x? I don't even know how to start this problem. Please help =)

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Question 610543: How do you prove that 1-cos2x=2sin^2x? I don't even know how to start this problem. Please help =)
Found 2 solutions by scott8148, stanbon:
Answer by scott8148(6628) (Show Source):
You can put this solution on YOUR website!
cos(2x) = cos^2(x) - sin^2(x)

1 - [cos^2(x) - sin^2(x)] = 2 sin^2(x)

1 - cos^2(x) + sin^2(x) = 2 sin^2(x)

1 - cos^2(x) = sin^2(x)

1 = sin^2(x) + cos^2(x)

Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
prove that 1-cos2x=2sin^2x
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1 - cos(2x) = 2sin^2(x)
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1 - (cos^2(x) - sin^2(x)) = 2sin^2(x)
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1-cos^2(x) + sin^2(x) = 2sin^2(x)
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sin^2(x) + sin^2(x) = 2sin^2(x)
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2sin^2(x) = 2sin^2(x)
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Cheers,
Stan H.
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