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Find the sum

  1. Apr 29, 2009 #1
    [tex]\Sigma_{n=1}^{ \infty} \frac{1}{(3n-2)(3n+1)} [/tex] I simplified it to partial fractions to (1/3) / (3n-2) - (1/3) / (3n+1) Now what?
  2. jcsd
  3. Apr 29, 2009 #2


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    An infinite number of terms cancel and a finite number of terms don't. Figure out which ones don't. Start writing out terms in the partial fraction expansion for n=1,2,3,4,5... if you need to. You should see the pattern pretty quickly.
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