A beautiful identical equation of the vector of the tetrahedrom
Xiao Zhang · Journal of Pingdingshan Teachers' College · 2003
At first,this article shows the concept of the outer normal vector of the tetrahedral area and then sets up an identical equation about the outer nomal vector of the area of the four sides of any tetrahedrom.From this,it puts foward the projection theorem and cosine laws of the tetrahedrom,and extends the result of the polyhedrom