       Re: Symbolic summation

• To: mathgroup at smc.vnet.net
• Subject: [mg101600] Re: [mg101561] Symbolic summation
• From: "David Park" <djmpark at comcast.net>
• Date: Fri, 10 Jul 2009 23:23:17 -0400 (EDT)
• References: <2688896.1247224403511.JavaMail.root@n11>

```Sum[Subscript[x, i], {i, 1, 5}]

Sum[Subscript[k, i], {i, 2, 3}]

Sum[k[i], {i, {1, 5, 7, c}}]

?

(A onetime memory of the missed Jens-Peer Kuska.)

David Park
djmpark at comcast.net
http://home.comcast.net/~djmpark/

From: Luca [mailto:Lucazanottifragonara at alice.it]

Hello all, I have a problem, I've to compute a symbolic summation, which
takes a very long time if I have to do it by hand. I have to write the terms
of the Volterra series, related to the associated linear equation of a
system.

The problem is that I'm not really confident with mathematica, I've tried to
use symbolic calculations with sums, but I think that in my case is not so
easy.

The problem is that I want a solution of this form:

x1+x2+x3+x4+x5...

Where the 1, 2, 3 and 4 and 5 are the summation subscripts...

My summation is not infinite, I have to stop it.

If I write something like this:

n = 3;

Sum[kl, {l, 2, n}]

I obtain 2kl, instead I want to obtain k2+k3.

Is it possible with mathematica?

```

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