设 F(x,y,z) = x*2+2y*2+3z*2 - 6 Fx' = 2x,Fy'= 4y,Fz' = 6z 法向量 n = {Fx',Fy',Fz'} |(1,1,1) = {2,4,6} // {1,2,3} 切平面方程 (x-1) + 2(y-1) + 3(z-1) =0 法线方程 (x-1)/1 = (y-1)/2 + (z-1)/3
