问题
填空题
（理科）若对于一切正实数x不等式
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答案
∵对于一切正实数x不等式
＞a恒成立4+2x2 x
由于
=4+2x2 x
+2x≥24 x
=4
×2x4 x
，2
∴
的最小值等于44+2x2 x
，可得a小于其最小值42
即可，2
∴a＜4
，2
故答案为 a＜4
．2
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（理科）若对于一切正实数x不等式
|
∵对于一切正实数x不等式
＞a恒成立4+2x2 x
由于
=4+2x2 x
+2x≥24 x
=4
×2x4 x
，2
∴
的最小值等于44+2x2 x
，可得a小于其最小值42
即可，2
∴a＜4
，2
故答案为 a＜4
．2
| 阅读下面对话，从方框内7个选项中选择5个恰当的句子完成此对话。 | |
| A: Hello, is that Wu Bin speaking? B: Yes. Who's that? A: This is Tian Hong. Are you free this Saturday evening? B: 1_______. A: I've got two tickets to Jay Chou's concert. 2_______. B: Certainly, I'd love to. He's my favorite singer. Thanks for your invitation. 3_______. A: Let's meet at the gate of the park at four o'clock. B: 4_______ I want to buy him a gift. A: OK. I'll get there at three. Shall we go to the shopping center to buy the gift? B: 5_______ See you then. A: See you.
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