在解析几何中,提到与二次曲线相切的问题,常常想到的是联立方程,然后由△=0得出关系式进行解答。一直以来我们都是这样教的,也是这样做的。然而,相切时△一定=0吗?退一步讲,就算是△=0,难道非要△=0吗?还有解决这类问题的其他方法吗?下边就以重庆近几年的两道高考题为例,分析如何从距离的角度来解决圆与二次曲线相切的问题。 In analytic geometry, the problem of tangency with the quadratic curve is mentioned, and the simultaneous equations are often thought of, and then the relationship is solved by Δ = 0. We have always taught this way, and we do the same. However, the tangential △ certain = 0? Take a step back, even if it is △ = 0, is it necessary △ = 0? There are other ways to solve such problems? Here to Chongqing in recent years, two As an example, this paper analyzes how to solve the problem that the tangent of the circle and the quadratic curve is from the perspective of distance.