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Homework Help: Closed Form Summation

  1. Sep 2, 2010 #1

    So here are my steps, which for some reason I feel are very wrong:

    Well in closed form would be [n(n+1)]/2 so 2k would be 2*[n(n+1)]/2
    For 1.7^k, I used a different form, which I dont have the formula for in front of me, but the final result for that part is [1.7^(n+1) - 1] /[1.7 - 1]

    So the final answer I got was [2*[n(n+1)]/2] + [1.7^(n+1) - 1] /[1.7 - 1]

    This feels incorrect to me for some reason. Can anyone confirm this or maybe this is correct?
  2. jcsd
  3. Sep 2, 2010 #2


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    You can check it yourself. Try a few sums for different values of n and see if the formula you derived gives the same answer. If it does, you can be reasonably sure you have the correct result.
  4. Sep 2, 2010 #3
    Well duh I dont know why I didnt think of that. Turns out my answer is correct. Thanks!
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