maxIter = 100; %max # of iterations
tol = 10.^-6.; %error tolerance
X = []; %sequence of nodes
a = 6.; %starting point
X(1.) = a;
pw = MypiecewiseFunction(x)
dpw = diff(pw, x)

for i = 1:maxIter
    X(i+1) = X(i) - (pw(X(i))/dpw(X(i)));
    if abs(X(i+1)-X(i)) < tol;
        disp(X)
        break;
    end
end



    function pw = MypiecewiseFunction(x)

        if x<0
            pw = -sqrt(-x);
        else
            pw =  sqrt(x);
        end


    end