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? > Thanks for any help you can give. > > 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