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Easy series

  1. Dec 12, 2011 #1
    1. The problem statement, all variables and given/known data

    [tex]1+2+3...+n[/tex]


    2. Relevant equations

    count the sum.


    3. The attempt at a solution

    it's such an easy sum to count but i just want to make sure.

    [tex]S_{n}=\frac{n}{2}(a_{1}+a_{n})[/tex]


    [tex]S_{n}=\frac{n}{2}(1+n)[/tex]


    [tex]S_{n}=\frac{n+n^{2}}{2}[/tex]
     
  2. jcsd
  3. Dec 12, 2011 #2
    Correct. Hope your anxiety is eased
     
  4. Dec 12, 2011 #3
    Lol its too simple idk why my teacher would give us something so simple I thought there would be a trick or something.
     
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