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MathGroup Archive 2007

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Re: Summations

  • To: mathgroup at
  • Subject: [mg78273] Re: [mg78228] Summations
  • From: Curtis Osterhoudt <cfo at>
  • Date: Wed, 27 Jun 2007 05:30:45 -0400 (EDT)
  • Organization: LANL
  • References: <>
  • Reply-to: cfo at

On Tuesday 26 June 2007 02:33:48 Sima wrote:
> Can someone please solve this summations:
> Summation(from i=1 to n) (i * a ^ i)
> Summation(from i=1 to m) (i * n ^ i + n ^ 3)
> you can mail me sollutions. Thanks

This looks suspiciously like a homework problem. Notice especially that once 
the first summation is done, the second one follows immediately and almost 
trivially from it. Googling the term "geometric series" might help immensely. 

Curtis Osterhoudt
cfo at
PGP Key ID: 0x4DCA2A10
Please avoid sending me Word or PowerPoint attachments

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