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

Re: Checking the sign of a Mathematical expression

• To: mathgroup at smc.vnet.net
• Subject: [mg66449] Re: Checking the sign of a Mathematical expression
• From: Paul Abbott <paul at physics.uwa.edu.au>
• Date: Sat, 13 May 2006 02:42:39 -0400 (EDT)
• Organization: The University of Western Australia
• References: <e3uodm$i9u$1@smc.vnet.net> <e418oq$h32$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

In article <e418oq$h32$1 at smc.vnet.net>,
 "Steve Luttrell" <steve_usenet at _removemefirst_luttrell.org.uk> wrote:

> Here are two examples of what you want:
> 
> Simplify[Sign[x^2],x>0]
> 1
> 
> Simplify[Sign[Sin[x]^2],0<x<Pi]
> 1

I think that Reduce is preferable:

  Reduce[x^2 > 0, x]

  Reduce[Sin[x]^2 > 0 && 0 <= x <= 2 Pi, x]

  Reduce[Sin[x]^2 > 0, x, Reals]

Cheers,
Paul

_______________________________________________________________________
Paul Abbott                                      Phone:  61 8 6488 2734
School of Physics, M013                            Fax: +61 8 6488 1014
The University of Western Australia         (CRICOS Provider No 00126G)    
AUSTRALIA                               http://physics.uwa.edu.au/~paul