特殊二次曲面中的圆

A special circle of quadric surface

二次曲面与平面的交线在空间解析几何中具有重要的作用,而二次曲面与平行于坐标平面的交线都是椭圆、双曲线、抛物线。与二次曲面的交线是圆的平面具有一定的特殊性,文章主要介绍特殊二次曲面的圆截面的求法。

The intersection of a plane with a quadric surface plays an important role in the space analytic geometry,and quadric surface parallel to the intersection of a coordinate plane is ellipse,hyperbola and parabola. The plane whose intersection with a quadric surface is round has certain particularity. This paper mainly introduces the method to get special circular cross section of quadric surface.