This is a beta course, so its structure, chapters, and examples may continue to change.二次曲面 This article is being translated. Please check back soon. Previous空间几何学习空间中点、直线、平面的方程及其位置关系。Next多元函数微分学将微分学的思想扩展到多个变量，研究偏导数、全微分及其应用。
