# Difference between revisions of "Power series - pointwise"

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A WASSERMANN (talk | contribs) |
A WASSERMANN (talk | contribs) |
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<p> | <p> | ||

nth-coefficient: <input type="text" id="input" value="1 / factorial(n)"> | nth-coefficient: <input type="text" id="input" value="1 / factorial(n)"> | ||

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</html> | </html> | ||

## Revision as of 09:17, 7 January 2019

Approximate the value of

- [math] \sum_{n=0}^\infty a_n\cdot x^n[/math]

for various values of [math]x[/math]. Drag the point 'x', the blue point shows the value of the above series.

nth-coefficient:

### The underlying JavaScript code

```
var board = JXG.JSXGraph.initBoard('jxgbox', {boundingbox:[-8,8,8,-8], axis:true, showClearTraces: true});
var p = board.create('glider', [0, 0, board.defaultAxes.x] , {name: 'x'});
var q = board.create('point', [0, 1], {name: '', color: 'blue', trace: true, fixed: true});
p.on('up', function(evt) {
var x, n, m = 50;
var txtraw = document.getElementById('input').value;
var a_n = board.jc.snippet(txtraw, true, 'n', true);
var s = 0;
x = p.X();
for (n = 0; n < m; n++) {
s += a_n(n) * Math.pow(x, n);
}
q.moveTo([x, s], 0);
});
```