Newton

by jmchen

HTML

<p id='result'> </p>

JavaScript

//
// pure newton to solve x^2 - 2 = 0
//
function fun(x) {
    return x*x - 2;
}

function dfun(x) {
    return 2*x;
}

var x = 1;
var i, imax = 20;
var eps = 1e-4;

for (i = 0; i < imax; i++) {
    console.log (x);
    x = x - fun(x)/dfun(x);
    if (fun(x) < eps) {
        break;
    }
}

// printout
document.getElementById('result').innerHTML=x;