[Date Index] [Thread Index] [Author Index]

Re: RealValued functions and derivatives

• To: mathgroup at smc.vnet.net
• Subject: [mg63413] Re: RealValued functions and derivatives
• From: David Bailey <dave at Remove_Thisdbailey.co.uk>
• Date: Fri, 30 Dec 2005 02:32:30 -0500 (EST)
• References: <dojesh$fo8$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Hello,

It might be better to post a little bit more of what you are trying to 
do. However, if you are manipulating a lot of expressions such as D[f,x]
(where f does not have a value) it can be helpful to simply define your 
own derivative - say dd[f,x] - and supply whatever rules you want for 
dd. You can also do something like expr /. dd->D to switch to the 
standard Mathematica derivative when you want to.

This may or may not help, depending on what exactly you are trying to do.

David Bailey
http://www.dbaileyconsultancy.co.uk