P(2ap, ap^2) and Q(2ap^2, ap&4) are two points on the parabola x^2=4ay.
I) show that the chord PQ has a gradient m=(1/2)(P^2 + P)
II) Find the minimum gradient of the chord PQ.
i could do part I pretty easily, but am struggling with part II, and the solution makes no sense to me at...