二次曲线方程的化简和位置的确定

Reducing Equations and Determining Positions of Guatric Cures

利用二次曲线的主方向、中心或顶点坐标 ,给出了使得曲线的简化方程由其不变量和半不变量表示的直角坐标变换公式 .

By use of principal directions and coordinates of center or apex of a quadric cure,a Descartes' orthogonal coordinate transformation formula such as the reduced equation of the cure is expressed in terms of its invariants and semi invariants.