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General term of a series

  1. Sep 21, 2014 #1
    1. The problem statement, all variables and given/known data

    Find the general term and test the nature of the series:

    2. Relevant equations

    1+1*4+1*4*7+...

    3. The attempt at a solution

    Term N = Term (N-1) * 3N-2

    Hence,3(N-1)-2 * 3N-2

    which simplifies to (3N-5)(3N-1) = 9N^2 - 18N + 5


    Is this correct?
     
  2. jcsd
  3. Sep 21, 2014 #2

    LCKurtz

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    No. Each term of your series has one more factor in it. So the nth term would have to written like$$
    a_n = 1\cdot 4 \cdot 7 ...(\text{something involving }n)$$where that "something" is a formula for the last factor of ##a_n##.
     
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