解析几何以坐标系为桥梁，将点用坐标表示，线用方程表达，进而达到用代数方法研究平面图形性质的目的．因此，解析几何的根本方法是坐标法、核心思想是数形结合与转换．由于圆是平面几何研究的主要对象之一，它的性质为学生所熟知，那么解析几何中再一次研究圆的目的和任务何 The analytical geometry uses the coordinate system as a bridge, the points are represented by coordinates, and the lines are expressed by equations, so as to achieve the purpose of using algebraic methods to study the nature of the planar graphs. Therefore, the fundamental method of parsing geometry is the coordinate method, the core idea is to combine and transform the number form. Since the circle is one of the main objects in the study of plane geometry, its nature is well known to students, so the purpose and task of the circle is again studied in analytical geometry.