有数学题.X,Y,Z为正数,且XYZ(X+Y+Z)=1,则(X+
X,Y,Z为正数,且XYZ(X+Y+Z)=1,则(X+Y)(Y+Z)的最小值是__
(x+y)(y+z)=xz+y(x+y+z)>+=2乘以根号下xzy(x+y+z)=2 当x=z=1,y=根号2-1时,(x+y)(y+z)取最小值2.