Re: Problem with using /.
- To: mathgroup at smc.vnet.net
- Subject: [mg69229] Re: Problem with using /.
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Sun, 3 Sep 2006 01:39:22 -0400 (EDT)
- Organization: The Open University, Milton Keynes, UK
- References: <edadil$pd0$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Nag wrote:
> Hello:
>
> I am trying to compute the moments of a distribution using the moment
> generating function, MGF[t,k]. Here is the relevant function for
> computing the j'th moment.
>
> M[j_, t_, k_] := D[MGF[t, k], {t, j}] /. {u -> 0, Sum[Subscript[p,
> i],{i, 0, k}] = 1};
>
> After taking the j'th derivative, need to set u to 0 and the sum of
> p(i)'s to 1.
Why have you replaced the rule sign -> sign by the = sign?
M[j_, t_, k_] := D[MGF[t, k], {t, j}] /. {u -> 0, Sum[Subscript[p, i],
{i, 0, k}] -> 1};
HTH,
Jean-Marc