Re: how to identify plane and measuring planar area

• To: mathgroup at smc.vnet.net
• Subject: [mg69242] Re: how to identify plane and measuring planar area
• From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
• Date: Sun, 3 Sep 2006 23:46:26 -0400 (EDT)
• Organization: The Open University, Milton Keynes, UK
• References: <eddq5a\$3t5\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```T Harris wrote:
> I am taking linear algebra and I have questions about the following code.
> Can someone run it and help me here?  These are the two questions --> (1)
> How do I measure the planar area of this flat thing?  (2)  What plane does
> this ellipsoid plot out on?
>
> What would I do in any case like this in the future to determine the plane?
>
> In[566]:=
> {xstretch,ystretch,zstretch} = {1.5,0.8,0};
> ranger=1.5;
> {slow,shigh} = {0,Pi};
> {tlow,thigh} = {0,2 Pi};
>
> hungellipsoidplot =
>   ParametricPlot3D[  xstretch   Sin[s]  Cos[t]  perpframe[1] +
>                      ystretch  Sin[s] Sin[t]  perpframe[2] +
>                      zstretch  Cos[s]perpframe[3], {s,slow,shigh},{t,tlow,
>       thigh},
>
>     PlotRange->{{-ranger,ranger},{-ranger,ranger},{-ranger,ranger}},
>               Axes->True,AxesLabel->{"x","y","z"},
>               Boxed->False,ViewPoint->CMView,DisplayFunction->Identity];
>
> setup =Show[hungellipsoidplot,frameplot,Axes3D[ranger],
>       DisplayFunction->\$DisplayFunction];
>
>
>
> Show[setup, ViewPoint -> 12 perpframe[1]];
>

Could you, please, post something that works -- your code does not work
at all -- or at least post all the required definitions -- definitions
of perpframe and CMView are missing -- and possibly something that is
syntacticly correct -- say a list of three functions when a list of
three functions is expected rather than the sum of three functions --
and also meaningful -- the Show of the Show command, even in disguised
of a setup expression, is quite meaningless -- ?

Here is the last of my attempts -- at least you get a plot -- before I
gave up:

Evaluate[Array[perpframe, 3]] = {1, 2, 3}
CMView = {1.3, -2.4, 2};
{ xstretch,ystretch,zstretch}= { 1.5,0.8,0};
ranger=1.5;
{ slow,shigh}= { 0,Pi};
{ tlow,thigh}= { 0, 2 Pi};\[IndentingNewLine]
hungellipsoidplot= ParametricPlot3D[ { xstretch Sin[s] Cos[t]
perpframe[1], ystretch Sin[s] Sin[t] perpframe[2], zstretch Cos[s]
perpframe[3]}, { s,slow,shigh}, { t,tlow,thigh}, PlotRange-> { {
-ranger,ranger}, { -ranger,ranger}, { -ranger,ranger}}, Axes->True,
AxesLabel-> { "x","y","z"}, Boxed->False, ViewPoint->CMView];

HTH,
Jean-Marc

```

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