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Need help evaluating this sum

  1. Sep 4, 2006 #1
    i need help evaluating this sum:

    (that is 100 P i, or the permutation)
     
    Last edited: Sep 17, 2008
  2. jcsd
  3. Sep 4, 2006 #2

    HallsofIvy

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    What does "100 P i" mean with i going from 1 to 100? Is P a constant?
     
  4. Sep 4, 2006 #3

    shmoe

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    I can't see your attatchment. Does 100 P i mean the number of permuations of i objects selected from 100? namely, 100 P i= 100!/(100-i)!

    What's being summed?
     
  5. Sep 4, 2006 #4
    yeah i'm sorry if it came out bad, but yeah it's the permutation
     
  6. Sep 4, 2006 #5

    shmoe

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    So what's being summed then?
     
  7. Sep 4, 2006 #6

    CRGreathouse

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    I'm going to take a stab in the dark and guess you mean

    [tex]\sum_{i=0}^n{}_{100}P_i[/tex]

    Am I close?
     
  8. Sep 4, 2006 #7
    yeap, that's exactly it. is there any explicit way to calculate the sum for arbitrary n?
     
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