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Re: I don't understand in Mathematic

• To: mathgroup@smc.vnet.net
• Subject: [mg10618] Re: [mg10551] I don't understand in Mathematic
• From: Levasseur <levasseu@bit-net.com>
• Date: Mon, 26 Jan 1998 04:42:49 -0500
• References: <199801202153.QAA00530@smc.vnet.net.>

alok. menghrajani wrote:
> 
> Hi,
> 
> I'm 16 and I can't understand how I (why me?) found this bug in
> mathematica. It's such a silly thing:
> 
> Solve [x/x+x=1, x] returns x=0 but if x=0 then x/x has no sence!
> 
> Bye, ALok
> 
> (Pls reply to my email: robot@writeme.com)
I assume that you mean Solve[x/x+x==1, x].  ( =  -> ==)

I THINK that the reason that Wolfram allows you you to get 0 for a
solution is that 0 is a removable singularity: Limit[x/x, x->0] is 1. 
The software explaination is the Solve doesn't have a HoldFirst
Attribute so it will simplify x/x before evaluation. 

Ken Levasseur
Math. Sci. UMass Lowell
http://www.uml.edu/Dept/Math/

• References:
  • I don't understand in Mathematic
    • From: alok.menghrajani@span.ch (alok. menghrajani)