已知1/x+1/y=3,1/x+1/z=4,1/y+1/z=5,则xyz=________
已知 x,y,z都是正实数,且 x+y+z=xyz 证明 (y+x)/z+(y+z)/x+(z+x)/y≥2(1/x+1
x+y+z=1 求xyz/(x+y)(y+z)(z+x)的最大值
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
已知x,y,z满足xyz=1,求证x^3/(x+y)+y^3/(y+z)+z^3/(z+x)大于等于3
已知x,y,z都是正数,且xyz=1,求证:x^2/(y+z)+y^2/(x+z)+z^2/(x+y)≥3/2
已知x^2+y^2+z^2=1,求证x+y+z-2xyz
已知正数xyz,满足x+y+z=xyz 已知正数x,y,z满足x+y+z=xyz,且不等式1/x+y+1/y+z+1/z
已知xyz满足x+y+z=30,3x+y-z=50,设t=5x+4y+2z 1当t=40时,求xyz的值 2若xyz均为
已知x:y:z=3:2:1,且x+y+z=12,则xyz=?
3道高数题,1,函数F(x,y,z)=(e^x) * y * (z^2) ,其中z=z(x,y)是由x+y+z+xyz=
已知实数x、y、z满足x+1/y=4,y+1/z=1,z+1/x=7/3,求xyz的值
先化简再求值3xyz+2(x^2y+y^2z-xyz)-xyz+2z^2x x=1 y= -1 z=2