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题目:2010年全国卷Ⅰ理科第21题:已知抛物线C:y2=4x的焦点为F,过点K(-1,0)的直线l与C相交于A,B两点,点A关于x轴的对称点为D。(1)证明:点F在直线BD上;(2)设FA.FB=
Title: National Volume I 2010 Subject 21: It is known that the focal point of the parabola C: y2 = 4x is F, the straight line passing K (-1,0) l intersects C with two points A and B, and point A is about The symmetry point of the x axis is D. (1) Proof: Point F on the straight line BD; (2) Let FA.FB =