Re: Graphics << Implicit vs ContourPlot

*To*: mathgroup at smc.vnet.net*Subject*: [mg122786] Re: Graphics << Implicit vs ContourPlot*From*: Bob Hanlon <hanlonr357 at gmail.com>*Date*: Thu, 10 Nov 2011 06:54:53 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <201111091124.GAA11084@smc.vnet.net>

Manipulate[ m = 2; t = theta Degree; del = 0.25; ContourPlot[{ (x Cos[t] + y Sin[t])^2/a^2 + (x Sin[t] - y Cos[t])^2/b^2 == 1, y == x, y == -x}, {x, -m, m}, {y, -m, m}, Frame -> False, Axes -> True, PlotRange -> 1.05 {{-m, m}, {-m, m}}], {{a, 2}, del, m, del, Appearance -> "Labeled"}, {{b, 1}, del, m, del, Appearance -> "Labeled"}, {{theta, 0}, -180, 180, 15, Appearance -> "Labeled"}] Bob Hanlon On Wed, Nov 9, 2011 at 6:24 AM, John Accardi <johnaccardi at comcast.net> wrote: > Goal: Show students a plot of both an ellipse with x axis as ellipse's > transverse axis > and the same ellipse in an x'y' coordinate plane that is rotated some angle > with respect the the original xy coordinate plane. (All in one plot) > > I used: > > << Graphics`ImplicitPlot`; ImplicitPlot[{7 x^2 - 6 Sqrt[3] x y + > 13 y^2 - 16 == 0, ((x^2)/2^2) + ((y^2)/2^2) == 1, y == = x, > y == -x}, {x, -3, 3}, AspectRatio -> 1.25] > > which works well but I had to hard fix the axis of rotation at 45 degrees > and plot it (y == x and y == -x). I also get an obsolete warning and > the suggestion to use the new ContourPlot for this in the future: > > General::obspkg: "\!\(\"Graphics`ImplicitPlot`\"\) is now obsolete. > The legacy version being loaded may conflict with current Mathematica > functionality. See the Compatibility Guide for updating information." > > So I try to accomplish the same graph with ContourPlot: > > ContourPlot[{7 x^2 - 6 Sqrt[3] x y + 13 y^2 - 16 == > 0, ((x^2)/2^2) + ((y^2)/2^2) == 1, y == x, y == -x, y == 0, > x == 0}, {x, -3, 3}, {y, -3, 3}, AspectRatio -> 1.25] > > which gets me close but I have lost traditional plotting of the xy axes > (no tick marks). Instead I get ContourPlots boxed style coordinate system. > > Question: How can I get my old style axes back in the context of > ContourPlot? > > Thank you for any insights. >

**References**:**Graphics << Implicit vs ContourPlot***From:*John Accardi <johnaccardi@comcast.net>