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RE: Evaluation and replacement?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg42510] RE: [mg42489] Evaluation and replacement?
  • From: "David Park" <djmp at earthlink.net>
  • Date: Sat, 12 Jul 2003 05:19:10 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

Jonathan,

Since 10 m does not appear in your expression (rule replacement doesn't do
algebra) you need a new rule.


10m -> 9m + n
newrule = #/10 & /@ %

10 m -> 9 m + n

m -> (1/10)*(9*m + n)

Then the replacement works.

20 m /. newrule
2 (9 m + n)

David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/


-----Original Message-----
From: AngleWyrm [mailto:no_spam_anglewyrm at hotmail.com]
To: mathgroup at smc.vnet.net
Subject: [mg42510] [mg42489] Evaluation and replacement?


Given a quantity 20m, and a rule 10m->9m+n, how can I get the result 18m+2n?

( m doesn't equal n; 10m degenerates into 9m + n. 9m doesn't degenerate into
8m+n.)
--
-Jonathan


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