(本讲适合高中 )圆锥曲线中求参数范围问题 ,是解析几何与函数、不等式、方程、三角等知识交叉、渗透的综合性问题 ,具有考查综合能力的功能 ,因而成为竞赛命题的热点 .1　基础知识探求圆锥曲线中的参数范围有以下常用方法 :( 1 )数形结合法根据含参数方程表示曲线的几何特征 , (This lecture is suitable for high school.) The problem of finding the range of parameters in a conic section is a comprehensive problem of the intersection and penetration of analytic geometry with functions, inequalities, equations, triangles, etc., and has the function of examining comprehensive abilities. Therefore, it has become a hot topic of contest propositions. The basic knowledge to explore the parameter range in the conic section has the following common methods: (1) The number and shape combination method expresses the geometric characteristics of the curve according to the parametric equation.