a locus+parabola+parametric question (1 Viewer)

[lollol]

P(2ap,ap^2) and Q(2aq,aq^2) are points on X^2=4ay, and the chord PQ subtends a right angle at the vertex O. show that pq=-4

 

[SoulSearcher]

O = (0,0)
P = (2ap,ap²)
Q = (2aq,aq²)

Find gradients of PO and QO, then use the fact that PO and QO are perpendicular to show that pq = -4