Difference between revisions of "Lagrange interpolation (dup)"

From JSXGraph Wiki
Jump to navigationJump to search
(New page: Construct a polynomial of degree 3 through four given points. <html> <link rel="stylesheet" type="text/css" href="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraph.css" /> <script type="tex...)
 
Line 3: Line 3:
 
<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>-->
 +
<script type="text/javascript" src="http://jsxgraph.uni-bayreuth.de/~alfred/jsxgraph/branches/0.70/src/loadjsxgraph.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 22:27, 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'});