Let a>0 and consider the parabola x2=4ay. A point P(k,2ak), where k is a real number, is taken in the plane.
(i) Substitute the coordinates of P in the equation of the parabola and obtain the condition that must be satisfied by k for P to lie on the curve.
(ii) Solve the condition obtained in part (i) to find all possible values of k in terms of a.
(iii) Hence write down the coordinates of every point of the form (k,2ak) that belongs to the parabola.