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Homework Help: Finding the sum of 2^n / n!

  1. Aug 5, 2007 #1
    I need to find the sum of 2^n/n! from n=2 to infinity, i know that it converges to e^x but how do i find the sum?
  2. jcsd
  3. Aug 5, 2007 #2
    It is e^2.
    Since x^n/n! sums to e^x substitute x=2 to get answer.
  4. Aug 5, 2007 #3
    Thanks, it was so simple -.-
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