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Math Help - More Proving

  1. #1
    Junior Member Dragon's Avatar
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    More Proving

    cos^2(2x)-cos^2(x)=sin^2(x)-sin^2(2x)
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  2. #2
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by Dragon View Post
    cos^2(2x)-cos^2(x)=sin^2(x)-sin^2(2x)
    Typically we do stuff to one side to make it equal to the other, but this one is much faster using standard manipulations:
    cos^2(2x)-cos^2(x)=sin^2(x)-sin^2(2x)

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

    1 = 1

    -Dan
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