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What identity is this?

  1. Feb 27, 2010 #1
    Cos^2 (wt+a) = 1+Cos(2wt+2a)

  2. jcsd
  3. Feb 27, 2010 #2


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    Hi Peon666! :smile:

    (have an omega: ω and try using the X2 tag just above the Reply box :wink:)
    (hmm … there's a factor of 2 missing :rolleyes: …)

    You need to learn all the standard trigonometric identities …

    this one is 2cos2x = 1 + cos2x

    (rather like 2sin2x = 1 - cos2x …

    try adding and subtracting them :wink:)
  4. Feb 27, 2010 #3
    I'm indeed ashamed that I'm studying Signals course and not aware of complete trigonometric identities. Thanks a lot for your help.
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