复切定理和蒙日定理的证明及研究

Proof and its study on double tangent and monge theorems

文中采用了射影几何的方法 ,证明了画法几何中关于两个二次曲面相交的著名的复切定理和蒙日定理 ,通过研究得出了周切线平面和交线平面成调和分割的性质 。

By means of projective geometry,the paper has proved the famous double tangent points and Monge theorems on two intersection quadric surface in descriptive geometry.Through study,the property is found out that planes cutting edgewise quadric curve and quadric intersections from the quadric surfaces become the harmonic division.The property is also found out that both quadric surfaces which have double tangent points have another quadric surface which cuts edgewise quadric curve from both known quadric surfa...