已知a,b,c∈R+,a+b+c=1,求证:(1a?1)(1b?1)(1c?1)≥1π∫4?416?x2dx

已知a,b,c∈R+,a+b+c=1,求证:(1a?1)(1b?1)(1c?1)≥1π∫4?416?x2dx.
2025-05-14 19:03:53
推荐回答(1个)
回答1:

证明:∵a+b+c=1,∴(

1
a
?1)(
1
b
?1)(
1
c
?1)=
b+c
a
×
a+c
b
×
a+b
c

∵a,b,c∈R+,∴
b+c
a
×
a+c
b
×
a+b
c
2
bc
a
×
2
ac
b
×
2
ab
c
=8
1
π
16?x2
dx
=
1
π
×
1
2
π×42
=8
(
1
a
?1)(
1
b
?1)(
1
c
?1)≥
1
π