圆锥曲线的定义是推导曲线方程的依据,也是研究曲线性质的理论基础．因此,利用定义解题是一种最直接、最本质的方法,能起到事半功倍的效果 The definition of the conic curve is the basis for deriving the curve equation, and it is also the theoretical basis for studying the nature of the curve. Therefore, using definition to solve problems is one of the most direct and essential methods that can achieve a multiplier effect.