Difference between revisions of "Lituus"

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Line 5: Line 5:
 
             [function(t){ return k1.Value()*b2.I([0,t],function(u){return Math.sin(u*u*0.5);}); },  
 
             [function(t){ return k1.Value()*b2.I([0,t],function(u){return Math.sin(u*u*0.5);}); },  
 
               function(t){ return k1.Value()*b2.I([0,t],function(u){return Math.cos(u*u*0.5);}); },
 
               function(t){ return k1.Value()*b2.I([0,t],function(u){return Math.cos(u*u*0.5);}); },
             0, Math.PI],
+
             0, 2*Math.PI],
 
             {strokewidth:4});       
 
             {strokewidth:4});       
 
</jsxgraph>
 
</jsxgraph>

Revision as of 10:24, 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>

External links