Difference between revisions of "Lagrange interpolation (dup)"

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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>
+
<!--<script type="text/javascript" src="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraphcore.js"></script>-->
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<script type="text/javascript" src="http://jsxgraph.uni-bayreuth.de/~alfred/jsxgraph/branches/0.70/src/loadjsxgraph.js"></script>
 
<form><input type="button" value="Add point" onClick="addPoint()"></form>
 
<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>

Revision as of 00:09, 11 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', [3,-1], {style:6});
        
        var polynomial = function(x) {
                var y = 0.0;
                for (var i=0;i<p.length;i++) {
                  var t = p[i].Y();
                  for (var k=0;k<p.length;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'});

        function addPoint() {
          p.push(board.createElement('point',[(Math.random()-0.5)*10,(Math.random()-0.5)*3],{style:6}));
          board.update();
        }