Difference between revisions of "Draggable exponential function"
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| + | Plot the function | ||
| + | :<math> y = e^{ax}</math> | ||
| + | where the parameter <math>a</math> is determined by the Point <math>A=(x_A, y_A)</math>. | ||
| + | |||
| + | That means, | ||
| + | :<math> a = log(y_A) / x_A </math> | ||
| + | |||
<jsxgraph width="400" height="400" box="box1"> | <jsxgraph width="400" height="400" box="box1"> | ||
| − | var board = JXG.JSXGraph.initBoard('box1', {boundingbox: [-5, 20, 5, - | + | var board = JXG.JSXGraph.initBoard('box1', {boundingbox: [-5, 20, 5, -2], axis:true}); |
| − | var | + | var A = board.create('point', [1, Math.exp(1)]); |
var graph = board.create('functiongraph', [ | var graph = board.create('functiongraph', [ | ||
function(x) { | function(x) { | ||
| − | var a = Math.log( | + | var a = Math.log(A.Y()) / A.X(); |
return Math.exp(a * x); | return Math.exp(a * x); | ||
}]); | }]); | ||
var txt = board.create('text', [-3, 10, function () { | var txt = board.create('text', [-3, 10, function () { | ||
| − | return "a = " + (Math.log( | + | return "a = " + (Math.log(A.Y()) / A.X()).toFixed(2); |
}], {fontSize: 16}); | }], {fontSize: 16}); | ||
</jsxgraph> | </jsxgraph> | ||
| + | <html> | ||
| + | <input type="button" onClick="alert('a = ' + (Math.log(A.Y()) / A.X()).toFixed(2))" value="Show value of a" /> | ||
| + | </html> | ||
| + | |||
| + | ===The JavaScript code=== | ||
| + | <source lang="javascript"> | ||
| + | var board = JXG.JSXGraph.initBoard('box1', {boundingbox: [-5, 20, 5, -2], axis:true}); | ||
| + | |||
| + | var A = board.create('point', [1, Math.exp(1)]); | ||
| + | var graph = board.create('functiongraph', [ | ||
| + | function(x) { | ||
| + | var a = Math.log(A.Y()) / A.X(); | ||
| + | return Math.exp(a * x); | ||
| + | }]); | ||
| + | |||
| + | var txt = board.create('text', [-3, 10, function () { | ||
| + | return "a = " + (Math.log(A.Y()) / A.X()).toFixed(2); | ||
| + | }], {fontSize: 16}); | ||
| + | </source> | ||
| + | |||
| + | <source lang="html4strict"> | ||
| + | <input type="button" onClick="alert('a = ' + (Math.log(A.Y()) / A.X()).toFixed(2))" value="Show value of a" /> | ||
| + | </source> | ||
[[Category:Examples]] | [[Category:Examples]] | ||
[[Category:Calculus]] | [[Category:Calculus]] | ||
Latest revision as of 11:41, 16 February 2016
Plot the function
- [math] y = e^{ax}[/math]
where the parameter [math]a[/math] is determined by the Point [math]A=(x_A, y_A)[/math].
That means,
- [math] a = log(y_A) / x_A [/math]
The JavaScript code
var board = JXG.JSXGraph.initBoard('box1', {boundingbox: [-5, 20, 5, -2], axis:true});
var A = board.create('point', [1, Math.exp(1)]);
var graph = board.create('functiongraph', [
function(x) {
var a = Math.log(A.Y()) / A.X();
return Math.exp(a * x);
}]);
var txt = board.create('text', [-3, 10, function () {
return "a = " + (Math.log(A.Y()) / A.X()).toFixed(2);
}], {fontSize: 16});
<input type="button" onClick="alert('a = ' + (Math.log(A.Y()) / A.X()).toFixed(2))" value="Show value of a" />
