Re: Coordinates for Implicit function
- To: mathgroup@smc.vnet.net
- Subject: [mg11708] Re: [mg11655] Coordinates for Implicit function
- From: Bob Hanlon <BobHanlon@aol.com>
- Date: Thu, 26 Mar 1998 03:08:38 -0500
Needs["Graphics`ImplicitPlot`"]
eqn = 3*x^2 - 4*x*y + 2*y^2 == 4;
thePlot = ImplicitPlot[eqn, {x, -5, 5}];
Extracting the data points from the Graphics object:
theData1 = thePlot[[1,2,1,1,1]];
theData2 = thePlot[[1,2,2,1,1]];
theData = Union[theData1, theData2];
If you want to generate your own data points
theTable = Table[{x, y /. Solve[eqn, y]}, {x, -2, 2, 0.1}]; theData =
Flatten[theTable /.
{{x_, {y1_, y1_}} -> {{x, y1}},
{x_, {y1_, y2_}} -> {{x, y1}, {x, y2}}}, 1];
I assume that "Conic" is some function which you have defined.
Bob Hanlon
In a message dated 3/19/98 10:23:34 PM, mavalosjr@aol.com wrote:
>How can I get the coordinates of an explicit function in this case the
>equation for
>an ellipse: 3 x^2 - 4 x y + 2 y^2 ==4? I tried using Table for the list
>but the method doesn't work for the two variables. Once having these
>coordinates I want to plug them into Map[Conic,{{x, y,}.....{xn,yn}} to
>get back the original equation.