关于相贯线两个实例的讨论

Discussion of Two Case on the Intersection Line of the stereoscopic Surface

本文对画法几何教材中相贯线的两个实例进行了深入研究．给出了相贯线投影上某一特殊点处曲线切线斜率的公式及其作切线的方法．

This paper studies two cases on the intersection line of the stereoscopic surface in the descriptive geometry teaching material. The formula of the curve tangent slope at some peculiar point in the orthograph on the stereoscopic surface intersecting line and the method of making tangent are given as well.