Difference between revisions of "Lituus"

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(21 intermediate revisions by one other user not shown)
Line 1: Line 1:
<jsxgraph width="500" height="500" box="box2">
 
b2 = JXG.JSXGraph.initBoard('box2', {axis:true,originX: 250, originY: 250, unitX: 25, unitY: 25});
 
var k1 = b2.createElement('slider', [[1,8],[5,8],[0,1,4]]);
 
var c = b2.createElement('curve',
 
            [function(t){ return k1.Value()*b2.I([0,t],function(u){return Math.sin(u*u);}); },
 
              function(t){ return k1.Value()*b2.I([0,t],function(u){return Math.cos(u*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 15: Line 4:
  
 
<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,boundingbox: [-10, 10, 10, -10]});
  var k = b1.createElement('slider', [[1,8],[5,8],[0,1,4]]);
+
  var k = b1.create('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.create('curve', [function(phi){return Math.sqrt(k.Value()/phi); }, [0, 0],0, 8*Math.PI],
             {curveType:'polar', strokewidth:4});       
+
             {curveType:'polar', strokewidth:1});       
 
</jsxgraph>
 
</jsxgraph>
  
 
===The JavaScript code to produce this picture===
 
===The JavaScript code to produce this picture===
  
<source lang="xml">
+
<source lang="javascript">
<jsxgraph width="500" height="500" box="box1">
+
var b1 = JXG.JSXGraph.initBoard('box1', {axis:true,boundingbox: [-10, 10, 10, -10]});
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 k = b1.createElement('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.createElement('curve', [function(phi){return Math.sqrt(k.Value()/phi); }, [0, 0],0, 8*Math.PI],
+
             {curveType:'polar', strokewidth:1});       
             {curveType:'polar', strokewidth:4});       
 
</jsxgraph>
 
 
</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});

External links