Power series for the exponential function

References

• http://en.wikipedia.org/wiki/Exponential_function

The underlying JavaScript code

board1 = JXG.JSXGraph.initBoard('jxgbox1', {boundingbox: [-6, 25, 6, -15], axis: true});
board1.suspendUpdate();

board1.create('functiongraph', 
    [function(t){ return Math.exp(t); },-10, 10],
    {strokeColor: "#cccccc"});

var s = board1.create('slider', [[0.75,-2],[5,-2.0],[0,0,15]], {name:'S',snapWidth:1});
board1.create('text',[-4,10, function() {
		return 'n='+s.Value();
	}
     ]);
board1.create('text',[-4,8, function() {
		var val = 0, i, sv = s.Value()+1;
		for(i = 0; i < sv; i++) {
   			val+= 1.0/JXG.Math.factorial(i);
		}
		return 'e~'+(val).toFixed(10);
	}
     ]);

board1.create('functiongraph', [
	function(t) {
		var val = 0, i, sv = s.Value()+1;
		for(i = 0; i < sv; i++) {
   			val+= Math.pow(t,i)/JXG.Math.factorial(i);
		}
		return val;
	},
-10, 10], {strokeColor: "#bb0000", curveType:'plot'});
board1.unsuspendUpdate();