A. B is two points on the parabola y ^ 2 = 2px, and OA is perpendicular to ob (o is the origin of coordinates). This paper proves that the product of abscissa and ordinate of a and B are fixed values

A. B is two points on the parabola y ^ 2 = 2px, and OA is perpendicular to ob (o is the origin of coordinates). This paper proves that the product of abscissa and ordinate of a and B are fixed values

Let a (Ya ^ 2 / 2p, ya), B (Yb ^ 2 / 2p, Yb), obviously, ya, Yb are not zero, from OA vertical ob, we have (Ya ^ 2 / 2P) * (Yb ^ 2 / 2P) + Ya * Yb = 0, and yayb is not zero, so we get (Ya * Yb / 4P ^ 2) + 1 = 0, Ya * Yb = - 4P ^ 2, and then XA * XB = (Ya ^ 2 / 2P) * (Yb ^ 2 / 2P) = 4P ^ 2