问题
选择题
已知实数m、n满足2m+n=2,其中mn>0,则
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答案
∵实数m、n满足2m+n=2,其中mn>0,
∴
+1 m
=2 n
(2m+n)(1 2
+1 m
)=2 n
(4+1 2
+n m
)≥4m n
(4+21 2
)=
?n m 4m n
(4+4)=4,当且仅当1 2
=n m
,2m+n=2,即n=2m=2时取等号.4m n
∴
+1 m
的最小值是4.2 n
故选A.