已知:xyz∈R+且x+y+z=1,求证:(1-x)(1-y)(1-z)≥8xyz该如何证明?

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已知:xyz∈R+且x+y+z=1,求证:(1-x)(1-y)(1-z)≥8xyz该如何证明?
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已知:xyz∈R+且x+y+z=1,求证:(1-x)(1-y)(1-z)≥8xyz该如何证明?
已知:xyz∈R+且x+y+z=1,求证:(1-x)(1-y)(1-z)≥8xyz
该如何证明?

已知:xyz∈R+且x+y+z=1,求证:(1-x)(1-y)(1-z)≥8xyz该如何证明?
1-x=y+z
1-y=x+z
1-z=x+y
由题意知x>0,y>0,z>0
y+z>=2根号y*根号z
x+z>=2根号x*根号z
y+x>=2根号y*根号x
(1-x)(1-y)(1-z)>=2根号y*根号z*2根号x*根号z*2根号y*根号x=8xyz
即(1-x)(1-y)(1-z)≥8xyz

1-x=y+z
1-y=x+z
1-z=x+y
由题意知x>0,y>0,z>0
y+z>=2根号y*根号z
x+z>=2根号x*根号z
y+x>=2根号y*根号x
(1-x)(1-y)(1-z)>=2根号y*根号z*2根号x*根号z*2根号y*根号x=8xyz
即(1-x)(1-y)(1-z)≥8xyz
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