Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Combination and summation notation.

  1. Aug 1, 2010 #1
    1. The problem statement, all variables and given/known data
    I am having trouble reading this notation

    [tex]\sum[/tex] (i/k)

    The sum is from i=0 to n

    I wasn't sure how to write the combination of i,k on the computer so I just wrote it as i/k.


    2. Relevant equations
    When I say combination I am talking about this formula n!/(k!(n-k)!)


    3. The attempt at a solution

    Is this just (0/k)+(1/k)+(2/k)...(n/k)

    I am sure I am interpeting it wrong but If I am not what do you do for situations where n is less than k because when you do the combination you get n!/(k!(n-k)!), and I don't think it is possible to do a negative factorial.
     
  2. jcsd
  3. Aug 1, 2010 #2

    rock.freak667

    User Avatar
    Homework Helper

    I don't think 'n' can be less than 'k' for the reason you said.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook