计算公式; 继而应用该公式求出在惯常的极坐标系中圆锥曲线曲率半径的统一表达式，并由此推出在惯常的直角坐标系中诸

圆锥曲线各自的曲率半径表达式.文章又利用行星轨道运动的相关动力学结论，直接推导出在惯常的极坐标系中圆锥曲线曲

率半径的统一表达式; 指出数学与力学推理方法的等价性，以及后者常常更加简便的原因.

coordinate system is derived respectively by using the rectangular coordinate calculation formula and mechanical

vector calculation formula of curvature radius of two-dimensional curve. Then the formula is used to get the uniform

expression of the curvature radius of the conic in the usual polar coordinate system，according which the expressions

of the curvature radius of each conic in the usual rectangular coordinate system are derived. This paper also uses the

relevant dynamic conclusions of planetary orbit motion to directly deduce the unified expression of curvature radius

of conic curve in the usual polar coordinate system，and points out the equivalence of mathematical and mechanical

reasoning methods，as well as the reason why the latter is often more simple.