在解析几何中,作为二次曲线的圆是研究直线的延续和学习圆锥曲线的基础.圆既是轴对称图形,又是中心对称图形,其中蕴藏着诸多位置关系和数量关系.对于解析几何中圆的某些问题,若能活用题中几何要素的关系,解题就会变得简单而快捷,现列举数例说明如下.1.运用“对称性”解题例1(2015年浙江高考文科卷改编)已知⊙C: In analytic geometry, the circle as a conic is the basis for studying the continuation of the line and learning the conic. The circle is both an axisymmetric graph and a centrosymmetric graph, which contains many positional and quantitative relationships. Some questions, if we can use the relationship between the geometric elements of the problem, the problem will become simple and fast, are listed below a few examples are as follows.1. Use the “Symmetry ” Solution 1 (2015 Zhejiang entrance examination Liberal arts volume adaptation) Known ⊙ C: