已知x,y,z∈R,求证:x^2+y^2>=xy+x+y-1

已知x,y,z∈R,求证:x^2+y^2>=xy+x+y-1 已知x,y,z∈R,若x^4+y^4+z^4=1,求证x^2+y^2+z^2≤根号3 已知x,y,z∈R+,且x+y+z=3,求证：x^2/（y^2+z^2+yz）+y^2/(x^2+z^2+zx）+z^2/(x^2+y^2+xy)≥1 证明 已知xyz∈R^+, x^2x * y^2y* z^2z≥x^y+x* y^z+x * z^x+y 已知x、y、z∈R＋,求证x⒋+y⒋+z⒋≥(x+y+z)xyz 已知x.y.z属于R,求证:(1+x^2)(1+y^2)(1+z^2)大于等于8xyz 若x,y,z∈R,且x+y+z=xyz,求证：(y+z)/x+(z+x)/y+(x+y)/z≥2(1/x+1/y+1/z)^2 若x,y,z∈R+,且x+y+z=xyz,求证:(y+z)/x+(z+x)/y+(x+y)/z＞2(1/x+1/y+1/z) 已知x,y,z∈R,且x+y+z=8,x^2+y^2+z^2=24,求证:4/3≤x≤3,4/3≤y≤3,4/3≤z≤3 已知x y z都属于R 2^x=3^y=6^z 求证 1/x+1/y=1/z 已知x,y,z∈（0,+∞）求证：√x^+xy+y^+√y^+yz+z^+√z^+zx+x^＞＝3/2(x+y+z ) 已知x,y,z∈ R,x+2y=z+6,x-y=3-2z,求x^2+y^2+z^2的最小值. 已知x,y∈R,求证:x^2+y^2≥xy+x+y-1 已知x,y,z 大于0,x+y+z=2,求证 xz/y(y+z)+zy/x(x+y)+yx/z(z+x)大于等于2/3 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. 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,xyz(x+y+z)=1,求证（x+y）(x+z)>=2 设x,y,z∈R+,求证 2z2-x2-y2/(x+y)+2x2-y2-z2/(y+z)≥x2+z2-2y2/(x+z)