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Math Help - [SOLVED] trig identities

  1. #1
    Member >_<SHY_GUY>_<'s Avatar
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    Question [SOLVED] trig identities

    i havent posted in a while, but i need some help in homework.

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

    i have a feeling that it involves one of the pythagorean identities, but i may be wrong.

    Thank you in advance :]
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    Before going forward are you absolutely certain the problem has been written correctly?
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  3. #3
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    Quote Originally Posted by ANDS! View Post
    Before going forward are you absolutely certain the problem has been written correctly?
    sorry, i took note that i wrote it incorrectly, its supposed to be:

    cos^2x
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    Ok well that makes a lot more sense. This one is fairly easy and you may well kick yourself. Remember that cos^{2}(x) is equal to 1-sin^{2}(x). From there it is elementary my dear Watson.
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    Quote Originally Posted by ANDS! View Post
    Ok well that makes a lot more sense. This one is fairly easy and you may well kick yourself. Remember that cos^{2}(x) is equal to 1-sin^{2}(x). From there it is elementary my dear Watson.
    i see my mistake, but thank you for your help sherlock
    haha
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