The common method to quadric surface equation is to get the Normal Component first, and then write out the equation through dot method.

求切平面方程的一般方法是先求切平面的法向量(借助偏导)，再用点法式写出切平面的方程。

youdao

The common method to quadric surface equation is to get the Normal Component first, and then write out the equation through dot method.

求切平面方程的一般方法是先求切平面的法向量(借助偏导)，再用点法式写出切平面的方程。

youdao