Analysis: Analysis: (1) Let the elliptic equation be? The two focal points and the two endpoints of the short axis are just the vertices of a square, and the length of the short axis is 2, from which the values of a, b and c can be obtained, and thus the elliptic equation can be obtained.

(2) The right focus f (1, 0), and the equation of the straight line L is y = x- 1. Let P(x 1, y 1) and Q(x2, y2), which are derived from the conditions set by the problem. What can you get from it? .

Answer: