Lagrange interpolation (dup): Difference between revisions
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Constructs a polynomial of degree n through n+1 given points. | |||
Points can be added by clicking on "Add point". | |||
<html> | <html> | ||
<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> | <script type="text/javascript" src="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraphcore.js"></script> | ||
<form><input type="button" value="Add point" onClick=" | <form><input type="button" value="Add point" onClick="addPoint()"></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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p[0] = board.createElement('point', [-1,2], {style:6}); | p[0] = board.createElement('point', [-1,2], {style:6}); | ||
p[1] = board.createElement('point', [0,-3], {style:6}); | p[1] = board.createElement('point', [0,-3], {style:6}); | ||
/* | |||
p[2] = board.createElement('point', [1,4], {style:6}); | p[2] = board.createElement('point', [1,4], {style:6}); | ||
p[3] = board.createElement('point', [2,1], {style:6}); | p[3] = board.createElement('point', [2,1], {style:6}); | ||
*/ | |||
var polynomial = function(x) { | var polynomial = function(x) { | ||
var y = 0.0; | var y = 0.0; | ||
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}; | }; | ||
graph = board.createElement('curve', ['x', polynomial, 'x', -10, 10], {curveType:'graph'}); | graph = board.createElement('curve', ['x', polynomial, 'x', -10, 10], {curveType:'graph'}); | ||
function addPoint() { | |||
p.push(board.createElement('point',[(Math.random()-0.5)*10,(Math.random()-0.5)*10],{style:6})); | |||
board.update(); | |||
} | |||
</script> | </script> | ||
</html> | </html> | ||
Revision as of 17:20, 3 December 2008
Constructs a polynomial of degree n through n+1 given points. Points can be added by clicking on "Add point".
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'});
