Re: imposing parameter assumptions
- To: mathgroup at smc.vnet.net
- Subject: [mg44195] Re: [mg44184] imposing parameter assumptions
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Sun, 26 Oct 2003 00:41:49 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
On Saturday, October 25, 2003, at 07:26 PM, drr7 wrote: > Simple question: How do I impose assumptions on the sign of > parameters in > symbolic equations and then test for the sign of an expression. > Example: > suppose I want to test the sign of f[a]=a^-3 if a<0. I tried > combinations > of Refine and Positive, but that does not seem to work for me. What I > am > really trying to do is sign a long expression for a derivative. > Thanks. > > > > Do you mean Simplify[Sign[a^3-3],a<0] -1 ? Andrzej Kozlowski Yokohama, Japan http://www.mimuw.edu.pl/~akoz/