在高中数学教材中,抛物线有一个重要性质:抛物线上的各点到焦点和准线的距离相等.下面试举几例,说明该性质在一些中考试题中的应用.例1(2008年镇江)如图1,在直角坐标系xOy中,点P为函数y=14x2在第一象限内图象上的任一点,点A的坐标为(0,1),直线l过点B(0,-1),且与x轴平行,过点P作y轴的平行线分别交x轴、l于点C、Q,连结AQ交x轴于点H,直线PH交y轴于点R. In high school mathematics textbooks, the parabola has an important nature: the parabola to focus on each point and the distance of the quasi-line below to give a few examples to illustrate the nature of some of the questions in the test. Example 1 (Zhenjiang 2008) As shown in Fig. 1, in Cartesian coordinate system xOy, the point P is the point where the function y = 14x2 at any point on the image in the first quadrant, the coordinates of point A are (0,1) 1), and parallel with the x-axis, over the point P for the y-axis parallel to the line to pay x-axis, l at the point C, Q, connecting the AQ cross x-axis at point H,