在2009年高考数学试题中,出现一点延展性较强的好题,不但让人耳目一新,也让人苦苦追寻,这些好题给研究者提供了很多素材.这里,我们研究其中的一个.题目(2009年湖北卷理科第20题)过抛物线y2=2px(p0)的对称轴上一点A(a,0)(a0)的直线与抛物线交于M、N两点,自M、N向直线:x=-a作垂 In 2009 college entrance examination mathematics questions, there is a little more ductile good topic, not only refreshing, but also people hard to pursue, these good questions to the researchers provide a lot of material. Here, we study one of them. (2009 Hubei Science Section 20) Parabola y2 = 2px (p0) The symmetry axis point A (a, 0) (a0) of the straight line and the parabola at M, N two points from the M, N to the straight line : x = -a for vertical