function r = Punto_Fijo(f, g, x1) 

k = 1;
while 1
    x2 = g(x1);
    %fprintf('%d %f %f\n', k, x1, f(x1));
    error = abs((x2-x1)/x2);
    if(error < 0.0000001) break;
    else x1 = x2;
    end;
    k = k+1;
end;
r = x2;