Re: Forcing numbers to be real.
- To: mathgroup at smc.vnet.net
- Subject: [mg29078] Re: [mg29069] Forcing numbers to be real.
- From: BobHanlon at aol.com
- Date: Sun, 27 May 2001 18:04:44 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
You can use TagSet to set upvalues for specific variables x /: Im[x] = 0; x /: Re[x] = x; {Re[x+y], Im[x+y]} {x + Re[y], Im[y]} Use the standard add-on package Algebra`ReIm` Use ComplexExpand if all variables are Real {Re[y+z], Im[y+z]} // ComplexExpand {y + z, 0} In version 4 or later use domain specifications in Simplify or FullSimplify Simplify[{Re[y+z], Im[y+z]}, Element[{y, z}, Reals]] {y + z, 0} Bob Hanlon In a message dated 2001/5/26 10:20:10 PM, REMOOVE_THIS_drkirkby at AND_THIS_ntlworld.com writes: >I've not used Mathematica much, but I know there is a way documented of >forcing Mathematica to consider a number to be real, so having an >imaginary part of 0. Can anyone tell me how to do it - I can't seem to >find it in the docs, although I know it is there somewhere. >