Re: Manipulating differential equations
- To: mathgroup at smc.vnet.net
- Subject: [mg18622] Re: Manipulating differential equations
- From: smudge at world.std.com (smudge)
- Date: Tue, 13 Jul 1999 01:01:39 -0400
- Organization: The World Public Access UNIX, Brookline, MA
- References: <7m6jti$2mc@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Martin Heimann (martin.heimann at bgc-jena.mpg.de) wrote: : Dear colleagues, : I would like to insert test functions into an expression that contains : differentials: : : dg1 = c''[x] + g c'[x] : : I would like e.g. to replace c[x] by Exp[-a x]: : : dg1/.c[x]->Exp[-a x] : : but this doesn't work; one has to put substitution rules for each of the : derivatives explicitly. Is there a more elegant way to achieve this? Try the following dg1 /. c -> (Exp[-a #]&)