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Re: Beginner question: operating on piecewise defined functions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg41620] Re: Beginner question: operating on piecewise defined functions
  • From: bobhanlon at aol.com (Bob Hanlon)
  • Date: Thu, 29 May 2003 08:13:45 -0400 (EDT)
  • References: <bb1v7e$9hc$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

f[x_] := 1+UnitStep[x-1]*(1/x^2-1);

Limit[FullSimplify[f[x], x>1], x->Infinity]

0

FullSimplify[Limit[f[x], x->Infinity],x>1]

0

f[Infinity]

0


Bob Hanlon

In article <bb1v7e$9hc$1 at smc.vnet.net>, Jan Rychter <jan at rychter.com> wrote:

<< Subject:	Beginner question: operating on piecewise defined functions
From:		Jan Rychter <jan at rychter.com>
To: mathgroup at smc.vnet.net
Date:		Wed, 28 May 2003 09:23:58 +0000 (UTC)

If I define a piecewise function as, say:

f[x_] := 1/x^2 /; x >= 1
f[x_] := 1 /; x < 1

then how can I get Mathematica to operate on it, as in:

Limit[f[x], {x->Infinity}]

Just trying that returns the expression unevaluated, even though
defining:

g[x_] := 1/x^2

and trying:
Limit[g[x], {x -> Infinity}]

Yields, as expected:

Out[7]=
{0}
 >><BR><BR>


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