Lituus: Difference between revisions
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<jsxgraph width="500" height="500" box="box1">  | <jsxgraph width="500" height="500" box="box1">  | ||
  var b1 = JXG.JSXGraph.initBoard('box1', {axis:true,  |   var b1 = JXG.JSXGraph.initBoard('box1', {axis:true,boundingbox: [-10, 10, 10, -10]});  | ||
  var k = b1.  |   var k = b1.create('slider', [[1,8],[5,8],[0,1,4]]);  | ||
  var c = b1.  |   var c = b1.create('curve', [function(phi){return Math.sqrt(k.Value()/phi); }, [0, 0],0, 8*Math.PI],  | ||
              {curveType:'polar', strokewidth:  |               {curveType:'polar', strokewidth:1});         | ||
</jsxgraph>  | </jsxgraph>  | ||
===The JavaScript code to produce this picture===  | ===The JavaScript code to produce this picture===  | ||
<source lang="  | <source lang="javascript">  | ||
var b1 = JXG.JSXGraph.initBoard('box1', {axis:true,boundingbox: [-10, 10, 10, -10]});  | |||
var k = b1.create('slider', [[1,8],[5,8],[0,1,4]]);  | |||
var c = b1.create('curve', [function(phi){return Math.sqrt(k.Value()/phi); }, [0, 0],0, 8*Math.PI],  | |||
              {curveType:'polar', strokewidth:1});         | |||
              {curveType:'polar', strokewidth:  | |||
</source>  | </source>  | ||
Latest revision as of 08:35, 8 June 2011
A lituus is a spiral in which the angle is inversely proportional to the square of the radius (as expressed in polar coordinates).
- [math]\displaystyle{ r^2\theta = k \, }[/math]
 
The JavaScript code to produce this picture
var b1 = JXG.JSXGraph.initBoard('box1', {axis:true,boundingbox: [-10, 10, 10, -10]});
var k = b1.create('slider', [[1,8],[5,8],[0,1,4]]);
var c = b1.create('curve', [function(phi){return Math.sqrt(k.Value()/phi); }, [0, 0],0, 8*Math.PI],
             {curveType:'polar', strokewidth:1});