直线与圆锥曲线位置关系的研究,集几何与代数于一身,揭示了转化、函数与方程、分类讨论、数形结合等重要的数学思想.综合考察了函数、方程、不等式,及学生的逻辑推理能力与运算能力,是高考考查的热点与难点.采用代数方法去研究,才能见微知著,这当然就离不开判别式的计算,本文就判别式的计算谈一下自己的做法. The study of the relationship between the position of the straight line and the conic, which integrates geometry and algebra, reveals the important mathematical ideas such as transformation, function and equation, classification and discussion, combination of number and shape, etc. It examines the functions, equations, inequalities and students’ logical reasoning Ability and computing power, is the hot and difficult college entrance examination test.Using algebraic methods to study, to see the micro-know, of course, can not do without the discriminant calculation, this article on the discriminant calculation to talk about their own practices.