Lagrange interpolation (dup): Difference between revisions
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<link rel="stylesheet" type="text/css" href="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraph.css" /> | <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/prototype.js"></script> | ||
<script type="text/javascript" src="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraphcore.js"></script> | |||
<div id="box" class="jxgbox" style="width:600px; height:400px;"></div> | <div id="box" class="jxgbox" style="width:600px; height:400px;"></div> | ||
<script language="JavaScript"> | <script language="JavaScript"> | ||
Revision as of 20:35, 2 December 2008
Construct a polynomial of degree 3 through four given points.
board = JXG.JSXGraph.initBoard('box', {originX: 250, originY: 250, unitX: 50, unitY: 25});
// Axes
b1axisx = board.createElement('axis', [[0,0], [1,0]], {});
b1axisy = board.createElement('axis', [[0,0], [0,1]], {});
var p = [];
p[0] = board.createElement('point', [-1,2], {style:6});
p[1] = board.createElement('point', [0,-3], {style:6});
p[2] = board.createElement('point', [1,4], {style:6});
p[3] = board.createElement('point', [2,1], {style:6});
var polynomial = function(x) {
var y = p[0].Y()*(x-p[1].X())*(x-p[2].X())*(x-p[3].X())/
((p[0].X()-p[1].X())*(p[0].X()-p[2].X())*(p[0].X()-p[3].X()))+
p[1].Y()*(x-p[0].X())*(x-p[2].X())*(x-p[3].X())/
((p[1].X()-p[0].X())*(p[1].X()-p[2].X())*(p[1].X()-p[3].X()))+
p[2].Y()*(x-p[0].X())*(x-p[1].X())*(x-p[3].X())/
((p[2].X()-p[0].X())*(p[2].X()-p[1].X())*(p[2].X()-p[3].X()))+
p[3].Y()*(x-p[0].X())*(x-p[1].X())*(x-p[2].X())/
((p[3].X()-p[0].X())*(p[3].X()-p[1].X())*(p[3].X()-p[2].X()));
return y;
};
graph = board.createElement('curve', ['x', polynomial, 'x', -10, 10], {curveType:'graph'});
