Re: Replace not spotting a replacement
- To: mathgroup at smc.vnet.net
- Subject: [mg103430] Re: [mg103399] Replace not spotting a replacement
- From: "David Park" <djmpark at comcast.net>
- Date: Mon, 21 Sep 2009 05:52:24 -0400 (EDT)
- References: <22608339.1253442945257.JavaMail.root@n11>
Replace does not Solve or do algebra. Replace only matches a pattern and that pattern does not occur in your expression. Solve for Tau in terms of Mu and then replace. Sqrt[2 \[Pi] \[Tau]] == \[Mu] \[Tau]sol = Part[Solve[%, \[Tau]], 1, 1] Sqrt[2 \[Pi]] \[Tau]^(3/2) /. \[Tau]sol David Park djmpark at comcast.net http://home.comcast.net/~djmpark/ From: claranet news [mailto:david at carter-hitchin.clara.co.uk] Hi Folks, Seems the replace function is being a bit dim here. This fails: Sqrt[2 \[Pi]] \[Tau]^(3/2) /. Sqrt[ 2 \[Pi] \[Tau]] -> \[Mu] Apologies if this is an FAQ - I couldn't see anything about it. What do I need to do here to coerce Mathematica into making this replacement? I tried using the Collect function on tau first, but that didn't seem to work. I also tried re-writing the replacement rule as Sqrt[2 \[Pi]] \[Tau]^(3/2) /. Sqrt[ 2 \[Pi] ] t^(1/2) -> \[Mu] But still no joy. Anyone know? Many thanks, David.