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Homework Help: I have forgotten my complex calculus!

  1. Nov 5, 2008 #1
    Can anyone help me with a complex calculus concept? I took this class years ago and cannot remember how to simplify something like [tex]\left|cos(1+2i)\right|[/tex]^2?


  2. jcsd
  3. Nov 5, 2008 #2


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    If a is a complex number, |a|2 = a * conjugate(a)

    where if a=x+iy, conjugate(a) = x-iy.

    So re-write cos(1+2i) in terms of exponentials and multiply.... something good probably comes out the other side
  4. Nov 5, 2008 #3
    Thanks! I'll try that. I think I actually remember now.

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