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Re: Defining a function

• To: mathgroup at smc.vnet.net
• Subject: [mg28588] Re: Defining a function
• From: "Paul Lutus" <nospam at nosite.com>
• Date: Mon, 30 Apr 2001 03:02:01 -0400 (EDT)
• References: <9cfrlf$gmd@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

"Jesse Marder" <yarblocks at yahoo.de> wrote in message
news:9cfrlf$gmd at smc.vnet.net...
> Hello.
>
> I have for example:
>
> a = x + y and
> b = x*y
>
> whats the procedure to express b as a function of a in Mathematica?

This is a simple algebra problem, and you cannot consistently express b as a
function of a. They are unrelated. Mathematica cannot get around this simple
fact.

Consider x = 0, y = 3. a = 3, b = 0

Consider x = 0, y = -3. a = -3, b = 0.

Consider x = -3, y = -3. a = -6, b = 9.

Consider x = 3, y = 3. a = 6, b = 9.

There's no relation.

--
Paul Lutus
www.arachnoid.com