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Summation with infinity

  1. Nov 21, 2009 #1
    1. The problem statement, all variables and given/known data

    what is the summation of a function where n=1 to n=infinity?

    For example, given a function sin[(pi)nt].

    2. Relevant equations

    3. The attempt at a solution

    I asking how I get that
    I do not know what should I do
  2. jcsd
  3. Nov 22, 2009 #2


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    Hi darkmagic! :smile:

    (have a pi: π and an infinity: ∞ :wink:)
    It's a different method in each case …

    just choose the one that seems easiest.

    In this case, either sum from n = 1 to N, and use the standard trigonometric identities for (sinA + sinB) etc, or (even easier :wink:) write it as Im(∑ einπt) :smile:
  4. Nov 22, 2009 #3


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    That is a Fourier series which is a huge field of mathematics in itself.
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