Difference between revisions of "Lituus"

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<jsxgraph width="500" height="500" box="box2">
 
<jsxgraph width="500" height="500" box="box2">
  b2 = JXG.JSXGraph.initBoard('box2', {axis:true,originX: 250, originY: 250, unitX: 25, unitY: 25});
+
  b2 = JXG.JSXGraph.initBoard('box2', {originX: 250, originY: 250, unitX: 25, unitY: 25});
  var k1 = b2.createElement('slider', [[1,8],[5,8],[0,1,4]]);
+
  var k1 = b2.createElement('slider', [[1,8],[5,8],[0,2,8]]);
 
  var len = b2.createElement('slider', [[1,7],[5,7],[1,2,4]]);
 
  var len = b2.createElement('slider', [[1,7],[5,7],[1,2,4]]);
 
  var c = b2.createElement('curve',  
 
  var c = b2.createElement('curve',  

Revision as of 10:27, 18 March 2009


A lituus is a spiral in which the angle is inversely proportional to the square of the radius (as expressed in polar coordinates).

[math]r^2\theta = k \,[/math]

The JavaScript code to produce this picture

<jsxgraph width="500" height="500" box="box1">
 var b1 = JXG.JSXGraph.initBoard('box1', {axis:true,originX: 250, originY: 250, unitX: 25, unitY: 25});
 var k = b1.createElement('slider', [[1,8],[5,8],[0,1,4]]);
 var c = b1.createElement('curve', [function(phi){return Math.sqrt(k.Value()/phi); }, [0, 0],0, 8*Math.PI],
             {curveType:'polar', strokewidth:4});      
</jsxgraph>

External links