Difference between revisions of "Lituus"
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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.create('slider', [[1,8],[5,8],[0,1,4]]); | 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], | var c = b1.create('curve', [function(phi){return Math.sqrt(k.Value()/phi); }, [0, 0],0, 8*Math.PI], | ||
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===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:1}); | ||
| − | |||
</source> | </source> | ||
Latest revision as of 10:35, 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]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});
