Re: symbolic and indefinite differentiation
- To: mathgroup at smc.vnet.net
- Subject: [mg35450] Re: symbolic and indefinite differentiation
- From: Francois Coppex <francoiscoppex at hotmail.com>
- Date: Sat, 13 Jul 2002 03:48:21 -0400 (EDT)
- References: <agjj4k$253$1@smc.vnet.net> <agm431$58n$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
> expr = Sum[a[k]*x^k, {k, 1, p}];
> D[expr, x] /. HoldPattern[Sum[a_, b__]] :> Sum[Evaluate[a], b]
>
> ???
I think that what he's trying to do is rather something like
p = 100;
Array[x, p];
f = Sum[x[i]^2, {i, 1, p}];
j = 43;
D[f, x[j]]
but leaving p and j undefined.