% Script to solve a system of nonlinear equations by 
% Newtons method. 
% It is probably more useful if you rewrite it into a function. 

% Define the problem. 
fun = @newton_ex;       % handle to a function [f,J]=fun(x)
x = [1;1;1];            % Initial guess. 
tol = 1.e-10;           % Tolerance

% Newton loop. 
for n=1:10
    [F,J] = feval(fun,x);
    d = -J\F;
    x = x+d
    if norm(d)<=tol
        break;
    end
end