Difference between revisions of "Archimedean spiral"
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It can be described in polar coordinates <math>(r, \theta)</math> by the equation | It can be described in polar coordinates <math>(r, \theta)</math> by the equation | ||
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with real numbers <math>a</math> and <math>b</math>. | with real numbers <math>a</math> and <math>b</math>. | ||
− | < | + | <jsxgraph height="500" width="500" box="jxgbox"> |
− | + | var board = JXG.JSXGraph.initBoard('jxgbox', {boundingbox: [-10, 10, 10, -10]}); | |
− | + | var a = board.create('slider', [[1,8],[5,8],[0,1,4]],{name:'a'}); | |
− | + | var b = board.create('slider', [[1,9],[5,9],[0,0.25,4]],{name:'b'}); | |
− | + | ||
− | + | var c = board.create('curve', [function(phi){return a.Value()+b.Value()*phi; }, [0, 0],0, 8*Math.PI], | |
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{curveType:'polar', strokewidth:4}); | {curveType:'polar', strokewidth:4}); | ||
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− | + | var g = board.create('glider', [c]); | |
− | + | var t = board.create('tangent', [g], {dash:2,strokeColor:'#a612a9'}); | |
− | </ | + | var n = board.create('normal', [g], {dash:2,strokeColor:'#a612a9'}); |
− | + | </jsxgraph> | |
+ | |||
===The JavaScript code to produce this picture=== | ===The JavaScript code to produce this picture=== | ||
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<source lang="javascript"> | <source lang="javascript"> | ||
− | + | var board = JXG.JSXGraph.initBoard('jxgbox', {boundingbox: [-10, 10, 10, -10]}); | |
− | + | var a = board.create('slider', [[1,8],[5,8],[0,1,4]],{name:'a'}); | |
− | + | var b = board.create('slider', [[1,9],[5,9],[0,0.25,4]],{name:'b'}); | |
− | + | ||
− | {curveType:'polar', strokewidth:4}); | + | var c = board.create('curve', [function(phi){return a.Value()+b.Value()*phi; }, [0, 0],0, 8*Math.PI], |
− | + | {curveType:'polar', strokewidth:4}); | |
− | + | ||
− | + | var g = board.create('glider', [c]); | |
+ | var t = board.create('tangent', [g], {dash:2,strokeColor:'#a612a9'}); | ||
+ | var n = board.create('normal', [g], {dash:2,strokeColor:'#a612a9'}); | ||
</source> | </source> | ||
[[Category:Examples]] | [[Category:Examples]] | ||
[[Category:Curves]] | [[Category:Curves]] |
Latest revision as of 13:35, 7 June 2011
It can be described in polar coordinates [math](r, \theta)[/math] by the equation
- [math]\, r=a+b\theta[/math]
with real numbers [math]a[/math] and [math]b[/math].
The JavaScript code to produce this picture
var board = JXG.JSXGraph.initBoard('jxgbox', {boundingbox: [-10, 10, 10, -10]});
var a = board.create('slider', [[1,8],[5,8],[0,1,4]],{name:'a'});
var b = board.create('slider', [[1,9],[5,9],[0,0.25,4]],{name:'b'});
var c = board.create('curve', [function(phi){return a.Value()+b.Value()*phi; }, [0, 0],0, 8*Math.PI],
{curveType:'polar', strokewidth:4});
var g = board.create('glider', [c]);
var t = board.create('tangent', [g], {dash:2,strokeColor:'#a612a9'});
var n = board.create('normal', [g], {dash:2,strokeColor:'#a612a9'});