Difference between revisions of "Change Equation of a Graph"

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This example shows how you can change the equation of a graph without creating the whole construction again.
 
This example shows how you can change the equation of a graph without creating the whole construction again.
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<html>
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<div style="width:960px">
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<div id="jxgbox" class="jxgbox" style="width:600px; height:400px; float:left; "></div>
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<p style="float:right">
 
<input type="text" id="eingabe" value="Math.sin(x)*Math.cos(x)">
 
<input type="text" id="eingabe" value="Math.sin(x)*Math.cos(x)">
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<input type="button" value="set" onClick="doIt()" style='margin:1em'>
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</p>
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</div>
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<br clear=all>
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<div id="debug" style="display:none;"></div>
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  <script type="text/javascript">
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    /* <![CDATA[ */
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        board = JXG.JSXGraph.initBoard('jxgbox', {originX: 250, originY: 250, unitX: 40, unitY: 20});
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// Axes
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        b1axisx = board.createElement('axis', [[1,0], [0,0]], {});
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        b1axisy = board.createElement('axis', [[0,1], [0,0]], {});
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eval("function f(x){ return "+document.getElementById("eingabe").value+";}");
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graph = board.createElement('curve', [function(x){ return x; }, function(x){ return f(x); }, "x", -10, 10]);
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//graph = eval("board.createElement('curve', [function(x){ return x; }, function(x){ return "+document.getElementById("eingabe").value+";}, 'x', -10, 10])");
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//graph.curveType = "graph";
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        p1 = board.createElement('glider', [graph], {style:6, name:'P'});
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        g = board.algebra.D(f);
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        p2 = board.createElement('point', [function() { return p1.X()+1;}, function() {return p1.Y()+board.algebra.D(graph.Y)(p1.X());}], {style:1, name:''});
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        l1 = board.createElement('line', [p1,p2],{});
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        p3 = board.createElement('point', [function() { return p2.X();}, function() {return p1.Y();}],{style:1, name:''});
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        pol = board.createElement('polygon', [p1,p2,p3], {});
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        t = board.createElement('text', [function(){return p1.X()+1.1;},function(){return p1.Y()+(p2.Y()-p3.Y())/2;},function(){ return "m="+(board.round(p2.Y()-p3.Y(),2));}]);
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        function doIt(){
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        eval("function f(x){ return "+document.getElementById("eingabe").value+";}");
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        graph.yterm = function(x){ return f(x); };  // usually: e.g. "x^2"
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//graph.yterm = eval("function(x){ return "+document.getElementById("eingabe").value+"; };");
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    graph.Y = graph.yterm;
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    graph.updateCurve();
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    board.update();
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        }
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  /* ]]> */
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  </script>
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</html>

Revision as of 11:37, 15 September 2008

This example shows how you can change the equation of a graph without creating the whole construction again.