# Difference between revisions of "Lagrange interpolation"

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Line 32: | Line 32: | ||

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() { |

## Latest revision as of 17:20, 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 = JXG.Math.Numerics.lagrangePolynomial(p);
var graph = board.create('functiongraph', [f,-10, 10], {strokeWidth:3});
var d1 = board.create('functiongraph', [JXG.Math.Numerics.D(f), -10, 10], {dash:1});
var d2 = board.create('functiongraph', [JXG.Math.Numerics.D(JXG.Math.Numerics.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();
}
```