Difference between revisions of "Lituus"
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| + | <jsxgraph width="500" height="500" box="box2"> | ||
| + | b2 = JXG.JSXGraph.initBoard('box2', {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(t){ return b2.I([0,t],function(u){return Math.sin(u)*Math.sin(u);}); }, | ||
| + | function(t){ return b2.I([0,t],function(u){return Math.sin(u)*Math.sin(u);}); }, | ||
| + | 0, 8*Math.PI], | ||
| + | {strokewidth:4}); | ||
| + | </jsxgraph> | ||
| + | |||
| + | |||
A '''lituus''' is a spiral in which the angle is inversely proportional to the square of the radius (as expressed in polar coordinates). | A '''lituus''' is a spiral in which the angle is inversely proportional to the square of the radius (as expressed in polar coordinates). | ||
| Line 4: | Line 15: | ||
<jsxgraph width="500" height="500" box="box1"> | <jsxgraph width="500" height="500" box="box1"> | ||
| − | 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.createElement('slider', [[1,8],[5,8],[0,1,4]]); | 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], | var c = b1.createElement('curve', [function(phi){return Math.sqrt(k.Value()/phi); }, [0, 0],0, 8*Math.PI], | ||
| Line 14: | Line 25: | ||
<source lang="xml"> | <source lang="xml"> | ||
<jsxgraph width="500" height="500" box="box1"> | <jsxgraph width="500" height="500" box="box1"> | ||
| − | 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.createElement('slider', [[1,8],[5,8],[0,1,4]]); | 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], | var c = b1.createElement('curve', [function(phi){return Math.sqrt(k.Value()/phi); }, [0, 0],0, 8*Math.PI], | ||
Revision as of 10:16, 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>
