Lagrange interpolation (dup): Difference between revisions
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<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> | <script type="text/javascript" src="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraphcore.js"></script> | ||
<form><input type="button" value="Add point" onClick="p.push(board.createElement('point',[Math.random(),Math.random()],{style:6}))"></form> | |||
<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"> | ||
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var polynomial = function(x) { | var polynomial = function(x) { | ||
var y = 0.0; | var y = 0.0; | ||
for (var i=0;i< | for (var i=0;i<p.length;i++) { | ||
var t = p[i].Y(); | var t = p[i].Y(); | ||
for (var k=0;k< | for (var k=0;k<p.length;k++) { | ||
if (k!=i) { | if (k!=i) { | ||
t *= (x-p[k].X())/(p[i].X()-p[k].X()); | t *= (x-p[k].X())/(p[i].X()-p[k].X()); | ||
Revision as of 17:17, 3 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 = 0.0;
for (var i=0;i<4;i++) {
var t = p[i].Y();
for (var k=0;k<4;k++) {
if (k!=i) {
t *= (x-p[k].X())/(p[i].X()-p[k].X());
}
}
y += t;
}
return y;
};
graph = board.createElement('curve', ['x', polynomial, 'x', -10, 10], {curveType:'graph'});
