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Re: How to draw several contours for one function, while

• To: mathgroup at smc.vnet.net
• Subject: [mg127709] Re: How to draw several contours for one function, while
• From: analysismath <loveinla at gmail.com>
• Date: Thu, 16 Aug 2012 01:56:36 -0400 (EDT)
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On Wednesday, August 15, 2012 3:39:24 AM UTC-4, Bob Hanlon wrote:
> Without knowing the functions it is difficult to guess the best way to
> 
> show what you might want to see. Manipulate may be a better way than
> 
> Animate to examine what is going on.
> 
> 
> 
> Manipulate[
> 
>  pts = {x, y} /.
> 
>    Solve[{
> 
>      f[x, y, a] == intersect,
> 
>      g[x, y, a] == 0},
> 
>     {x, y}, Reals];
> 
>  Show[
> 
>   ContourPlot[f[x, y, a],
> 
>    {x, -8, 8}, {y, -8, 8},
> 
>    Contours -> Range[0, 75, 15],
> 
>    ContourStyle -> Hue /@ (.7 Range[0, 1, 15/75] + .15),
> 
>    ContourShading -> None,
> 
>    ContourLabels -> All],
> 
>   ContourPlot[g[x, y, a] == 0,
> 
>    {x, -8, 8}, {y, -8, 8},
> 
>    ContourShading -> None,
> 
>    ContourLabels -> All],
> 
>   Graphics[{Red, AbsolutePointSize[4],
> 
>     Tooltip[Point[#], #] & /@ pts}],
> 
>   PlotRange -> {{-8, 8}, {-7, 8}}],
> 
>  {{a, 0}, -5, 5, .5, Appearance -> "Labeled"},
> 
>  {{intersect, 0}, 0, 75, 5, Appearance -> "Labeled"},
> 
>  Initialization :> {
> 
>    f[x_, y_, a_] = (x - a/2)^2 + (y - a/4)^2 - 2,
> 
>    g[x_, y_, a_] = x + y - a}]
> 
> 
> 
> 
> 
> Bob Hanlon
> 
> 
> 
> 
> 
> On Tue, Aug 14, 2012 at 4:24 AM,  <loveinla at gmail.com> wrote:
> 
> > Dear all,
> 
> >
> 
> > Suppose I have two implicit functions, say, F(x, y) and G(x, y); both involve a parameter a.
> 
> >
> 
> > In one Animate, I need:
> 
> >  (1) several contours for function F(x, y) with its Max and Min values;
> 
> >  (2) only one contour for function G(x, y)==0.
> 
> >  (3) because I need to see how they change as parameter a changes, I want to use Animate to generate animation.
> 
> >
> 
> > Can anybody help? Thanks.
> 
> >

Thank you very much, Bob.

• References:
  • How to draw several contours for one function, while only one contour
    • From: loveinla@gmail.com