处理解析几何中的中点弦问题通常有两种解题思路:一是设而不求,采用点差法得到中点坐标与弦所在直线的斜率的关系,从而解决问题;二是方程的思想,联立直线和圆锥曲线得到二次方程,利用韦达定理得到中点坐标与斜率的关系,使问题得以解决.若能进一步 There are usually two solutions to solving the mid-point string problem in analytical geometry: one is to set up instead of seeking, and the point-difference method is used to get the relationship between the mid-point coordinate and the slope of the line where the string is located so as to solve the problem. Second, The simultaneous straight line and the conic obtained quadratic equation, the use of Vednda's theorem to get the coordinates of the midpoint and the slope of the relationship so that the problem can be solved .If you can further