二次曲线的利用不变性作图法刘德金（山东德州师专２２１０００）［１］和［２］两文各自提出一种不经过坐标变换作出二次曲线图形的直接作图法，避免了坐标平移与旋转等复杂的计算．本文将提出另一种二次曲线的直接作图法—二次曲线的利用不变性作图法，以使我们对“数”... The use of invariant plotting methods for quadratic curves Liu Dejin (Dezhou Teachers College, Shandong 221000) [1] and [2] each proposed a direct drawing method for making quadratic curves without coordinate transformation, avoiding coordinate translation. With complex calculations such as rotations. This article will propose another method of direct plotting of the quadratic curve—the quadratic curve using invariance plotting method...