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MathGroup Archive 2005

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Re: Sum

  • To: mathgroup at smc.vnet.net
  • Subject: [mg55227] Re: [mg55175] Sum
  • From: Sseziwa Mukasa <mukasa at jeol.com>
  • Date: Thu, 17 Mar 2005 03:28:54 -0500 (EST)
  • References: <200503161035.FAA23742@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

On Mar 16, 2005, at 5:35 AM, mjumbo wrote:

> Can sombody explain me why
>
> Sum[Exp[- k], {k, 0, Infinity}]
>
> gives the correct result, while the following (imho equivalent) 
> statements
>
> x = Exp[-k]
> Sum[x, {k, 0, Infinity}]
>
> don't? What should I do to make it work? It is rather vexing to 
> copy/paste long expressions instead of using short placeholders like 
> x.

Sum evaluates its arguments in a nonstandard way,

Sum[Evaluate[x],{k,0,Infinity}]

works.

Regards,

Ssezi


  • References:
    • Sum
      • From: mjumbo <mjumbo@nm.ru>
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