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,originX: 250, originY: 250, unitX: 25, unitY: 25}); | var b1 = JXG.JSXGraph.initBoard('box1', {axis:true,originX: 250, originY: 250, unitX: 25, unitY: 25}); | ||
| − | 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> | ||
| Line 15: | Line 15: | ||
<jsxgraph width="500" height="500" box="box1"> | <jsxgraph width="500" height="500" box="box1"> | ||
var b1 = JXG.JSXGraph.initBoard('box1', {axis:true,originX: 250, originY: 250, unitX: 25, unitY: 25}); | var b1 = JXG.JSXGraph.initBoard('box1', {axis:true,originX: 250, originY: 250, unitX: 25, unitY: 25}); | ||
| − | 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> | ||
</source> | </source> | ||
Revision as of 09:46, 22 July 2010
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.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});
</jsxgraph>
