极坐标系以及在极坐标系中两点间的距离公式,直线方程、圓的方程,圆锥曲线的统一方程,由方程讨论曲线的对称性,直角坐标与极坐标的互化等问题在一般的平面解析几何的教科书中都有较详尽的叙述。本文就上述以外的某些问题作了一些讨论,这对进一步理解极坐标系是有必要的。 The polar coordinate system and the distance formula between two points in the polar coordinate system, the equations of the straight line, the equation of the circle, the unified equation of the conic curve, the symmetry of the curve discussed by the equations, the inter-relation of the rectangular coordinates and the polar coordinates, etc. There are more detailed descriptions in the textbooks of plane analytic geometry. This article makes some discussion on some issues other than the above, which is necessary to further understand the polar coordinate system.