平面的法向量是指:如果表示向量的有向线段所在直线垂直于平面α,则称这个向量为平面α的法向量。一个平面的法向量有无数多个,它们方向相同或相反。熟悉并掌握法向量的概念,深入挖掘其相关性质,充分发挥其在解题中的作用,对于提高我们分析问题、解决问题能力大有裨益。 The normal vector of the plane means: If the line representing the directed line segment of the vector is perpendicular to the plane α, then the vector is called the normal vector of the plane α. There are countless multiples of a plane’s normal vector, which are in the same or opposite direction. Familiarity with and mastering the concept of the normal vector, in-depth excavation of its relevant nature, and give full play to its role in solving problems, will greatly benefit our ability to analyze problems and solve problems.