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Re: Plot3D question

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  • Subject: [mg70687] Re: Plot3D question
  • From: Bill Rowe <readnewsciv at>
  • Date: Mon, 23 Oct 2006 02:50:19 -0400 (EDT)

On 10/22/06 at 1:19 AM, dimmechan at (dimitris) wrote:

>I would like to apologise for the mistakes which obviously contained
>my previous post. Here comes the correct one:

>I would like to know why the Plot3D function does not complain about
>the following command (note there is a singularity at y=0)

>Plot3D[Sin[x]/y, {x, -10, 10}, {y, -10, 10}]

>whereas it does complain (a lot!) about the following

>Plot3D[Sin[x]/y, {x, -10, 10}, {y, 0, 10}]

>I believe it has to do with the non-adaptive algorithm used by
>Plot3D, but even the command

I believe Plot3D always samples at the end points of the 
variable range. So, in the first example the singularity doesn't 
cause a problem as Sin[x]/y is not sampled at y = 0. But in the 
second example, the singularity is an end point for y and is sampled.

>Plot3D[Sin[x]/y, {x, -10, 10}, {y, -10, 10},PlotPoints->100]

>does not change the behavior.

Which should be expected if I have the correct understanding of Plot3D.
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