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Homework Help: Fourier Series Representation of Signals (Proof)

  1. Jan 26, 2013 #1
    Hi guys,

    I was studying the proof below and just can't figure out the the first highlighted step leads to the second and I was wondering if you guys can help me to fill that in. (:


    Thank you so much for your help in advance guys!
  2. jcsd
  3. Jan 26, 2013 #2


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    Gold Member

    It follows from:

    cos(a+b)= cos(a)cos(b)-sin(a)sin(b)
  4. Jan 26, 2013 #3
    Thank you so much! :D
  5. Jan 26, 2013 #4
    -- it's okay, I for it. Really stupid question. hahaha ---
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