(2) Let M(x0, y0) N(x0, -y0)

TM * TN =(x0+2)2-y0 ^ 2 = 5x 0 ^ 2/4+4x 0+3x 0 =-8/5。

R 2 = 13/25。

(3) let p (x 1, y1) k (pm) = (y1-y0)/(x1-x0) k (pn) = (y1+y0.

Let's subtract the two-point elliptic equations of formulas m and n, not formula m.

(x 1+x0)/4+k(PM)(y 1+y0)= 0

|or|*|os|=4(x 1^2y0^2-x0^2y 1^2)/(x 1^2-x0^2)

Substitute y12 =1-x12/4y02 =1-x02/4.

|OR|*|OS|=4