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Re: Division by zero, despite strong hint

  • To: mathgroup at smc.vnet.net
  • Subject: [mg96590] Re: [mg96542] Division by zero, despite strong hint
  • From: Curtis Osterhoudt <cfo at lanl.gov>
  • Date: Mon, 16 Feb 2009 16:41:31 -0500 (EST)
  • Organization: LANL
  • References: <200902161155.GAA03397@smc.vnet.net>
  • Reply-to: cfo at lanl.gov

  Hi, David, 

         Just a missing comma between the arguments to Piecewise!  Try
g3[x_] := Piecewise[{{Sin[1/x], x != 0}, {0, x == 0}}]

                       Regards, 
                              C.O.


On Monday 16 February 2009 04:55:40 am dch888 wrote:
> Hi,
> 
> I'm trying to plot the Sin[1/x] curve with the curve being defined as
> 0 at 0 like this:
> 
> g3[x_] := Piecewise[{{Sin[1/x], x != 0} {0, x == 0}}]
> 
> Invoking Plot produced a flat graph; puzzled I asked for g3[0] and
> got:
> 
> Power::infy Infinite expression 1/0 encountered >>
> 
> {
>  {Indeterminate, False True},
>  {0, \!\(\*
>     TagBox["True",
>      "PiecewiseDefault",
>      AutoDelete->False,
>      DeletionWarning->True]\)}
> }
> 
> Hmmm...  what's the trick here to stop Mathematica evaluating all the branches
> of the piecewise fn? There's nothing in the documentation that I can
> see to stop this in Piecewise... perhaps I need to use a different Mathematica 
> function?
> 
> Thanks,
> David.
> 
> 



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