Logarithmic spiral: Difference between revisions
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A WASSERMANN (talk | contribs) (New page: It can be described in polar coordinates <math>(r, \theta)</math> by the equation :<math>r = ae^{b\theta}\,</math> with real numbers <math>a</math> and <math>b</math>. <html> <link rel="...) |
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var a = board.createElement('slider', [[1,-1],[5,-1],[0,1,4]]); | var a = board.createElement('slider', [[1,-1],[5,-1],[0,1,4]]); | ||
var b = board.createElement('slider', [[1,-2],[5,-2],[0,0.25,4]]); | var b = board.createElement('slider', [[1,-2],[5,-2],[0,0.25,4]]); | ||
var c = board.createElement('curve', [function(phi){return a.Value()*board.pow(Math.E,phi); }, [0, 0],'phi',0, 8*Math.PI], | var c = board.createElement('curve', [function(phi){return a.Value()*board.pow(Math.E,b.Value()*phi); }, [0, 0],'phi',0, 8*Math.PI], | ||
{curveType:'polar', strokewidth:4}); | {curveType:'polar', strokewidth:4}); | ||
</script> | </script> | ||
Revision as of 17:25, 10 February 2009
It can be described in polar coordinates [math]\displaystyle{ (r, \theta) }[/math] by the equation
- [math]\displaystyle{ r = ae^{b\theta}\, }[/math]
with real numbers [math]\displaystyle{ a }[/math] and [math]\displaystyle{ b }[/math].
The JavaScript code to produce this picture
<link rel="stylesheet" type="text/css" href="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraph.css" />
<script type="text/javascript" src="http://jsxgraph.uni-bayreuth.de/distrib/prototype.js"></script>
<script type="text/javascript" src="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraphcore.js"></script>
<div id="jsxgbox" class="jxgbox" style="width:500px; height:500px;"></div>
board = JXG.JSXGraph.initBoard('jsxgbox', {originX: 250, originY: 250, unitX: 50, unitY: 50});
var a = board.createElement('slider', [[1,-1],[5,-1],[0,1,4]]);
var b = board.createElement('slider', [[1,-2],[5,-2],[0,0-25,4]]);
var c = board.createElement('curve', [function(phi) a.Value()+b.Value()*phi; }, [0, 0],'phi',0, 8*Math.PI],
{curveType:'polar', strokewidth:4});
