法向量n=(Fx,Fy,Fz)=(1/2√x,1/2√y,1/2√z)则任意一点,设为(x0,y0,z0)的切平面为1/2√x0(x-x0)+1/2√y0(y-y0)+,1/2√z0(z-z0)=0截距分别为,√a*√x0,√a*√y0,√a*√z0√a*√x0+√a*√y0+√a*√z0=√a*(√x0+√y0+...