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Homework Help: Sum of a geometric series

  1. Dec 14, 2011 #1
    1. The problem statement, all variables and given/known data
    I already counted [tex]V_{0}=-1[/tex]

    and [tex]q=\frac{1}{3}[/tex]

    given: [tex]V_{n}=1-\frac{2}{U_{n}}[/tex]





    2. Relevant equations

    count: [tex]\sum_{k=0}^{n}V_{k}[/tex]


    3. The attempt at a solution


    i counted the sum and i got : [tex]((\frac{1}{3})^{n+1}-1)(\frac{2}{3})[/tex]

    is that correct?
     
  2. jcsd
  3. Dec 14, 2011 #2

    Simon Bridge

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    What is Un ... don't make us make assumptions.
     
  4. Dec 15, 2011 #3
    I got it anyway. It's


    [tex]S=-\frac{3}{2}(1-(\frac{1}{3})^{n+1})[/tex]
     
  5. Dec 15, 2011 #4

    Simon Bridge

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    Well done.
     
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