x1 = 2.;
x = newton(@f, @dfdx, x1, 20);

length(x) 

function y = f(x)
% F demonstrate the case of no-convergence for Newton's method
    if x > 0
        y = sqrt(x);
    else
        y = -sqrt(-x);
    end
end

function y = dfdx(x)
% DFDX demonstrate the case of no-convergence for Newton's method
    if x > 0
        y = 1/(2*sqrt(x));
    elseif x < 0
        y = 1/(2*sqrt(-x));
    else
        y = 0;
    end
end