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Homework Help: Series (Partial Sums )

  1. Apr 3, 2009 #1
    1. The problem statement, all variables and given/known data

    How to find the Sn of this patial sum : 1/n+3 - 1/ n+1 ??

    2. Relevant equations

    Finding the terms

    3. The attempt at a solution
    In fact, I tried finding s1 and s2 and so on till s6 and I found that the Sn is -1/ n+2 after I canceled the terms, is that right ??
  2. jcsd
  3. Apr 3, 2009 #2


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    If Sn= 1/(n+3)- 1/(n+1) then Sn+1= 1/(n+4)- 1/(n+2). Subtracting these two consecutive partial sums gives
    [tex]]\frac{1}{n+4}- \frac{1}{n+2}- \frac{1}{n+3}+ \frac{1}{n+1}[/tex]
    What does that give you?
  4. Apr 3, 2009 #3
    Are you trying to say that this method gives us Sn term directly, without a need for any subs. and finding terms ???
    Last edited: Apr 3, 2009
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