【摘要】 轨迹是点、线、面按一定条件运动时历经的空间。本文用投影的方法描述几何元素的运动规律使空间轨迹问题的研究具有直观性 ,并在此基础上进行数学分析使问题具有一般性。更多还原

【Abstract】 The trace is a space collection across which geometric elements are moved based on given conditions.This article applies the projection method to describing the law of moving geometric elements,which gives visibility to the trace problem. A mathematical analysis on this basis generalizes the problem.更多还原