Re: How is it possible to factor Sum[a]+Sum[b] to Sum[a+b] ?
- To: mathgroup at smc.vnet.net
- Subject: [mg42044] Re: How is it possible to factor Sum[a]+Sum[b] to Sum[a+b] ?
- From: "Steve Luttrell" <luttrell at _removemefirst_westmal.demon.co.uk>
- Date: Tue, 17 Jun 2003 05:43:29 -0400 (EDT)
- References: <bcjtid$hn3$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
This will will define the property you need: Unprotect[Sum]; Sum /: Sum[a_[n_], {n_, 1, Infinity}] + Sum[b_[n_], {n_, 1, Infinity}] := Sum[a[n] + b[n], {n, 1, Infinity}]; Protect[Sum]; You could make more a general definition if you want to widen the scope of the transformation rule. -- Steve Luttrell West Malvern, UK "Eric Duault" <eduault at yahoo.com> wrote in message news:bcjtid$hn3$1 at smc.vnet.net... > Hello > > I looking for a way to transform an expression in the form > Sum[a[n], {n, 1, Infinity}] + Sum[b[n], {n, 1, Infinity}] > to : > Sum[a[n]+b[n], {n, 1, Infinity}] > where a[n] and b[n] are numerical. > > I tried quite a faw Mathematica fuctions, but none of the gives the required > result. > There is still the possibility to define custom transformation rules, but > Mathematica should provide a function for doing that. > > Thank you for your answer. > > > >