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MathGroup Archive 2006

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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


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