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Trouble Writing Sum

  1. Nov 23, 2013 #1

    Qube

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    Gold Member

    1. The problem statement, all variables and given/known data

    I'm having trouble writing a sum for this:

    https://scontent-b-mia.xx.fbcdn.net/hphotos-frc3/v/1420232_10201136345792485_382911431_n.jpg?oh=ebd9432103184956c863370121e326ce&oe=529332ED

    2. Relevant equations

    delta x = (b-a)/n

    n = 4
    b-a = 2
    delta x = 1/2

    3. The attempt at a solution

    I keep writing this. But we can't solve this for anything; 4/i when i = 0 is infinity. What am I doing wrong?

    https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-prn1/v/536211_10201136357192770_1062632899_n.jpg?oh=c155bbe6c53633a848621aacfcffc055&oe=52931A0F&__gda__=1385430375_4a3d5c0ebb07b3aaff69a8869b9a8da5
     
  2. jcsd
  3. Nov 23, 2013 #2

    SteamKing

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    Staff Emeritus
    Science Advisor
    Homework Helper

    For one thing, f(x) = 2/x. IDK what 4/i is supposed to represent.
     
  4. Nov 23, 2013 #3

    Qube

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    Gold Member

    I think the issue here is finding the correct general term for xi and the correct bounds of summation.

    I did it again, and this time for the general term I am using i/2 + 1, and the bounds of summation as i = 0 and i = 3.

    I find that drawing a sketch helps. Immensely.

    https://scontent-b-mia.xx.fbcdn.net/hphotos-prn2/v/1469817_10201136445594980_301054541_n.jpg?oh=0d3937e4a716935b821122e27ba1781d&oe=5292C107
     
    Last edited: Nov 23, 2013
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