已知xyz属于R,x+y+z=1,求证x方+y方+z方大于等于1/3

已知xyz属于R,x+y+z=1,求证x方+y方+z方大于等于1/3 已知x.y.z属于R,求证:(1+x^2)(1+y^2)(1+z^2)大于等于8xyz 设x,y,z属于R+,求证:x^4+y^4+z^4=(x+y+z)xyz 已知xyz属于R+,x+y+z=1,求证x^3/(y(1-y))+y^3/(z(1-z))+z^3/(x(1-x))大于等于1/2 x,y,z属于R,且xyz（x+y+z）=1,求证（x+y）（y+z）≥2 已知:xyz∈R+且x+y+z=1,求证:(1-x)(1-y)(1-z)≥8xyz该如何证明? 数学不等式题：x.y.z属于R+,xyz(x+y+z)=1 求（x+y)(y+z)最小值 已知x,y,z∈R+,且x+y+z=8,xyz=5,求证：x,y,z中至少有一个小于1 已知x^2+y^2+z^2=1,求证x+y+z-2xyz 已知x,y,z>0,xyz(x+y+z)=1,求证（x+y）(x+z)>=2 已知x,y,z∈R+.求证(1+x2)(1+y2)(1+z2)≥8xyz 已知X,Y,Z属于R+ ,且X+2Y+3Z=3,则XYZ的最大值 已知xyz∈R+求证:(1+x²)(1+y²)(1+z²)≥8xyz 已知x、y、z∈R＋,求证x⒋+y⒋+z⒋≥(x+y+z)xyz 已知x、y、z∈R+,xyz=1,求证：x/(1+xy)+y/(1+yz)+z/(1+zx)≥3/2. 已知 X+Y+Z=a xyz∈R+ 求证X^2+Y^2+Z^2>=(1/3)a^2 已知x+y+z=0求证x*x*x+y*y*y+z*z*z=3xyz 已知xyz满足z+y+z=xyz 求证：x(1-y2)(1-z2)+y(1-x2)(1-z2)+z(1-x2)(1-y2)=4xyz