function[xn,k,info,Jk] = newtonsis2(f1 ,f2 ,df11 ,df12 ,df21 ,df22 ,kmax ,tol ,xc)
info=0;
F0(1)= f1(xc) ; F0(2)= f2(xc);
Fk=F0 ;

for k=1:kmax
    Jk(1,1)= df11(xc) ; Jk(1,2)= df12(xc) ; Jk(2,1)= df21(xc) ; Jk(2,2)= df22(xc);
    xn=xc-(inv(Jk))*Fk' ;
    Fk(1)= f1(xn) ; Fk(2)= f2 (xn);
    if norm( xn -xc)< tol && norm(Fk)< tol
        return
    end
    xc=xn;
end
info=1;
end