# Difference between revisions of "Lagrange interpolation"

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Line 11: | Line 11: | ||

p[0] = board.create('point', [-1,2], {size:4}); | p[0] = board.create('point', [-1,2], {size:4}); | ||

p[1] = board.create('point', [3,-1], {size:4}); | p[1] = board.create('point', [3,-1], {size:4}); | ||

− | var f = | + | var f = JXG.Math.Numerics.lagrangePolynomial(p); |

var graph = board.create('functiongraph', [f,-10, 10], {strokeWidth:3}); | var graph = board.create('functiongraph', [f,-10, 10], {strokeWidth:3}); | ||

− | var d1 = board.create('functiongraph', [ | + | var d1 = board.create('functiongraph', [JXG.Math.Numerics.D(f), -10, 10], {dash:1}); |

− | var d2 = board.create('functiongraph', [ | + | var d2 = board.create('functiongraph', [JXG.Math.Numerics.D(JXG.Math.Numerics.D(f)), -10, 10], {dash:2}); |

function addPoint() { | function addPoint() { |

## Revision as of 16:19, 20 February 2013

Constructs a polynomial of degree [math]n[/math] through [math]n+1[/math] given points. Points can be added by clicking on "Add point". The dotted line is the graph of the first derivative, the dashed line is the graph of the second derivative.

### References

### The underlying JavaScript code

```
var board = JXG.JSXGraph.initBoard('box', {boundingbox: [-5, 10, 7, -6], axis: true});
var p = [];
p[0] = board.create('point', [-1,2], {size:4});
p[1] = board.create('point', [3,-1], {size:4});
var f = board.lagrangePolynomial(p);
var graph = board.create('functiongraph', [f,-10, 10], {strokeWidth:3});
var d1 = board.create('functiongraph', [board.D(f), -10, 10], {dash:1});
var d2 = board.create('functiongraph', [board.D(board.D(f)), -10, 10], {dash:2});
function addPoint() {
p.push(board.create('point',[(Math.random()-0.5)*10,(Math.random()-0.5)*3],{size:4}));
board.update();
}
```