题目内容
已知x,y∈(0,2),且xy=1,则
+
的最小值是______.
| 2 |
| 2-x |
| 4 |
| 4-y |
∵x,y∈(0,2),且xy=1,
∴
+
=
=
=1+
≥1+
=1+
=1+
=
,
即
+
≥
,当且仅当2x=4y 时,等号成立,
故答案为
.
∴
| 2 |
| 2-x |
| 4 |
| 4-y |
| 16-2x-4y |
| (2-x)(4-y) |
| 16-2x-4y |
| 9-2x-4y |
| 7 |
| 9-(2x+4y) |
| 7 | ||
9-2
|
| 7 | ||
9-4
|
7(9+4
| ||
| 49 |
16+4
| ||
| 7 |
即
| 2 |
| 2-x |
| 4 |
| 4-y |
16+4
| ||
| 7 |
故答案为
16+4
| ||
| 7 |
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