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>