在涉及二次曲线的问题中,经常出现“垂直”这个几何条件,许多同学对此不知所措．本文举一例说明如何在代数问题中使用“垂直”这个几何条件．题目已知抛物线y=ax2+bx+c与x 轴交于A、B两点,Q(2,k)是抛物线上一点,且 AQ⊥BQ,求ak的值．(浙江绍兴市中考题) 分析在此题中,AQ⊥BQ这个条件似 In the problems involving quadratic curves, the geometric condition of “vertical” often appears, and many students are overwhelmed. This article gives an example of how to use the “vertical” geometric condition in algebraic problems. It is known that the parabola y=ax2+bx+c crosses the x-axis at points A and B, Q(2,k) is a point on the parabola, and AQ⊥BQ, find the value of ak. (Zhejiang Shaoxing City Examination Questions) Analysis In this question, AQ⊥BQ