If P, Q, R are three points on a parabola `y^2=4ax` whose ordinates are in geometrical progression, then the tangents at P and R meet on :

On the parabola y^2 = 4ax , three points E, F, G are taken so that their ordinates are in geometrical progression. Prove that the tangents at E and G intersect on the ordinate passing through F .

If p,q,r are in one geometric progression and a,b,c are in another geometric progression, then ap, bq, cr are in

If y_(1),y_(2) are the ordinates of two points P and Q on the parabola and y_(3) is the ordinate of the intersection of tangents at P and Q, then