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