Re: Ellipse and circle intersection
- To: mathgroup at smc.vnet.net
- Subject: [mg38381] Re: Ellipse and circle intersection
- From: Tom Burton <tburton at brahea.com>
- Date: Fri, 13 Dec 2002 04:09:50 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
On 12/11/02 11:39 PM, in article 01b301c2a18c$2f9f7d30$3f57fea9@Tomas,
"Tomas Garza" <tgarza01 at prodigy.net.mx> wrote:
> I thought the problem was straightforward and wrote
>
> ellipse = (x - c)^2/b^2 + (y - d)^2/a^2 == 1;
> circ = x^2 + y^2 == 1;
> sol = Solve[{ellipse, circ}, {x, y}];
>
> The output comes out immediately as a rather long expression...
Everything works just fine for me:
$Version
4.2 for Mac OS X (June 4, 2002)
example1={a->1.2,b->1.3,c->.2,d->.3};
example2={a->1.2,b->1.3,c->1.2,d->1.3};
sol1=sol/.example1
sol2=sol/.example2
pts1={x,y}/.Select[sol1,FreeQ[#,_Complex]&];
pts2={x,y}/.Select[sol2,FreeQ[#,_Complex]&];
<<Graphics`ImplicitPlot`
pe1=ImplicitPlot[ellipse/.example1,{x,-2,2}];
pe2=ImplicitPlot[ellipse/.example2,{x,-2,3}];
pc1=ImplicitPlot[circ/.example1,{x,-2,2}];
pc2=ImplicitPlot[circ/.example2,{x,-2,3}];
pp1=Graphics[{PointSize[0.03],Point/@pts1}];
pp2=Graphics[{PointSize[0.03],Point/@pts2}];
Show[pe1,pc1,pp1,pe2,pc2,pp2];
Tom Burton