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Re: Picewise Function

• To: mathgroup at smc.vnet.net
• Subject: [mg82090] Re: Picewise Function
• From: Girish Kulkarni <geeree at gmail.com>
• Date: Fri, 12 Oct 2007 02:48:21 -0400 (EDT)
• References: <fek98d$lae$1@smc.vnet.net>

Frank Hechtner wrote:
> Now i want mathematica to tell that this function uses a specific
> domain. The function should only be defined if the result of the
> evaluation is <= 0.25.

This sounds like you want to restrict the *range* of the function and
not its domain. In that case simply discard the value that the
function returns if it is greater than 0.25.

OTH, if you have to restrict the *domain*, you can use Condition
( /; ). See `Condition' in Mathematica help. For example:

  q[x_] := x^2 /; x > 0
  q[x_] := -x^2 /; x <= 0

defines a function piecewise. It evaluates to x^2 if x is positive and
to -x^2 if it is not.

--
Girish Kulkarni - Allahabad, India - http://girish.50webs.com