Re: Sum
- To: mathgroup at smc.vnet.net
- Subject: [mg55221] Re: [mg55175] Sum
- From: "David Park" <djmp at earthlink.net>
- Date: Thu, 17 Mar 2005 03:28:41 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
Why not use...
x = Exp[-k];
Sum[x // Evaluate, {k, 0, Infinity}]
E/(-1 + E)
or even better
f[k_] := Exp[-k]
Sum[f[k], {k, 0, Infinity}]
E/(-1 + E) ??
David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/
From: mjumbo [mailto:mjumbo at nm.ru]
To: mathgroup at smc.vnet.net
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.
__________