设新函数f（x,y,z,μ,ρ）=x*x+y*y+z*z+μ（x*x+y*y-z）+ρ（x+y+z-1）,分别对x,y,z,μ,ρ求导,即df（x,y,z,μ,ρ）/dx=0
df（x,y,z,μ,ρ）/dy=0
df（x,y,z,μ,ρ）/dz=0
df（x,y,z,μ,ρ）/dμ=0
df（x,y,z,μ,ρ）/dρ=0
,联立方程组求解即可