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Re: Creating a sign chart

  • To: mathgroup at
  • Subject: [mg98936] Re: Creating a sign chart
  • From: Jens-Peer Kuska <kuska at>
  • Date: Wed, 22 Apr 2009 05:11:37 -0400 (EDT)
  • Organization: Uni Leipzig
  • References: <gsivd0$9aa$>
  • Reply-to: kuska at


f[x_, y_] := x*y*Exp[-x^2 - y^2]

   Sign[Det[{{D[f[x, y], {x, 2}], D[f[x, y], x, y]},
            {D[f[x, y], x, y], D[f[x, y], {y, 2}]}}]]], {x, -2,
   2}, {y, -2, 2}]


or what ever a sign chart is ..


davef wrote:
> Is it possible to render a sign chart in Mathematica 10?
> Typically a sign chart is used with the first and second derivatives to identify extrema.  I know there are other ways to convey this information.  However, in my case I  need to demonstrate a sign chart by means of an illustation.  I can create a graphic in Visio and import into Mathematica but I would prefer if there were a means of generating such a chart directly in Mathematica.
> Something like:
> +++++++++++++++------------
> Thanks for any ideas.
> Dave
> x2373

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