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Mathematica solution with an imaginary part

  1. Mar 31, 2008 #1
    Can someone please explain why the result of the following has an imaginary part when I put it into mathematica 6.0?

    Code (Text):
    Sum[Sin[n 6]/2^n, {n, 1, Infinity}]
     
  2. jcsd
  3. Mar 31, 2008 #2
    Because
    Code (Text):
    Sin[n 6] / 2^n
    is
    Code (Text):
    2^-n * Sin[n 6]
     
  4. Apr 1, 2008 #3
    Wrap it in a full simplify command:

    Code (Text):
    FullSimplify[Sum[Sin[n 6]/2^n, {n, 1, Infinity}]]
     
  5. Apr 1, 2008 #4
    So what?
     
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