我们知道,圆锥曲线(包括椭圆、双曲线、抛物线)存在统一定义,这使它们之间存在许多共性,并由此可以形成解决这些相应问题的通法.比如在有关圆锥曲线的焦点弦问题中,它们就存在着许多共同之处,而且可以借助同一背景——直角梯形来解决.图1如图1,设F为圆锥曲线(只画出一部分)的焦 We know that there is a uniform definition of conical curves (including ellipses, hyperbolas, and parabolas), which gives them a lot of commonality, and thus can form a common solution to these problems. For example, in the focus chord problem concerning conic curves. , they have a lot in common, and can be solved with the aid of the same background - right-angle trapezoid. Figure 1 As shown in Figure 1, let F be a conic section (only a part of the coke)