Conic sections in polar form

From JSXGraph Wiki
The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.

The equation of the curve is

[math]\displaystyle{ \, r = \frac{p}{1-\epsilon\cdot cos(\phi+\rho)}; }[/math]


 

The JavaScript code to produce this picture

var brd = JXG.JSXGraph.initBoard('jxgbox',{axis:true,boundingbox: [-12, 10, 12, -10]});
var p = brd.create('slider',[[2,8],[6,8],[0,3,6]]); brd.createElement('text',[1,8,'p:']);
var eps = brd.create('slider',[[2,7],[6,7],[-6,0.5,6]]); brd.createElement('text',[1,7,'ε:']);
var len = brd.create('slider',[[2,6],[6,6],[0,3,6]]); brd.createElement('text',[1,6,'len:']);
var rho = brd.create('slider', [[2,5],[6,5],[0,0,2*Math.PI]]); brd.createElement('text',[1,5,'ρ:']);
var f = brd.create('curve', 
   [function(phi) { return p.Value()/(1-eps.Value()*Math.cos(phi+rho.Value())); }, [1,0], 0,function(){return len.Value()*Math.PI}],      
   {curveType:'polar', strokewidth:2, strokeColor:'#CA7291'}
  );        
var q = brd.create('glider', [f], {style:6,name:'G'}); 
brd.create('tangent', [q], {dash:3}); 
brd.addHook(function(){document.getElementById('ausgabe').innerHTML = (p.Value()).toFixed(1) + "/(1 - (" + (eps.Value()).toFixed(1) + ")*cos(φ+"+(rho.Value()).toFixed(1) +"))";});