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Re: (a-b)/(c-d)=!=(b-a)/(d-c) ???

• To: mathgroup at smc.vnet.net
• Subject: [mg13012] Re: (a-b)/(c-d)=!=(b-a)/(d-c) ???
• From: "Le Van Tri" <lvtri at cs.uwm.edu>
• Date: Tue, 30 Jun 1998 00:26:09 -0400
• Organization: University of Wisconsin - Milwaukee
• References: <6n4oke$nj7@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

This could fix for you:

Unprotect[Simplify];
Simplify[Equal[x_,y_]]/;(y=!=0):=Equal[Simplify[x-y],0];
Unprotect[TrueQ];
TrueQ[x_]/;(Head[x]=!=Simplify):=If[Simplify[x],True,False];

Tim Dellinger wrote in message <6n4oke$nj7 at smc.vnet.net>...
>How come
>(a-b)/(c-d) === (b-a)/(d-c)
>
>returns False, i.e. TrueQ[ (a-b)/(c-d) =!= (b-a)/(d-c) ]  returns True,
>
>but
>
>(a-b)/(c-d) === Simplify[ (b-a)/(d-c) ]
>
>returns True ???
>
>Why does mere simplification change anything? I'm using Mathematica
>3.0.?  on win95.
>
>
>--
>--
>"Perhaps my most deeply rooted hobby is to understand         Tim
>Dellinger
> the mechanisms of simple and familiar
>tdelling at uiuc.edu
> natural phenomena." Irving Langmuir
>http://www.ews.uiuc.edu/~tdelling
>