P(t = 2) is a point on the parabola y2=4ax. What is the point of the intersection of tangent at P and the directrix of the parabola?
A tangent is drawn at the point P(α,β) on the parabola y2=4ax. This tangent meets a second parabola y2=4a(x+k) at A and B, what is the midpoint of AB?