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Re: imposing parameter assumptions

• To: mathgroup at smc.vnet.net
• Subject: [mg44196] Re: [mg44184] imposing parameter assumptions
• From: "Peter Pein" <nospam at spam.no>
• Date: Sun, 26 Oct 2003 00:41:50 -0400 (EDT)
• References: <200310251026.GAA16281@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Simplify[Sign[a^-3], a < 0]
   -1

use FullSimplify for harder problems.

Peter Pein, Berlin
petsie at arcAND.de
replace && by || to write to me


----- Original Message -----
From: "drr7" <rondeau at uvic.ca>
To: mathgroup at smc.vnet.net
Subject: [mg44196] [mg44184] imposing parameter assumptions


> 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.
>
>

• References:
  • imposing parameter assumptions
    • From: "drr7" <rondeau@uvic.ca>