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问题 填空题

函数f（x）=2x2-kx+3在[2，+∞）上是增函数，则k的取值范围是______．

答案

∵f（x）=2x2-kx+3的对称轴为：x=

k
4

∴函数的单调增区间为：[

k
4
，+∞）

又∵函数f（x）=2x2-kx+3在[2，+∞]上是增函数

∴[2，+∞)⊆[

k
4
，+∞)

∴

k
4
≤2   解可得，k≤8

故答案为：（-∞，8]．

阅读理解

     Tim, Sonia, Jim, Tina, Jenny and Ann are in the classroom. They find (发现) a pencil-box, a ruler, a

pencil and a notebook on the desk. Tim asks Sonia, "Is this your pencil?" Sonia answers, "Yes, it is.

Thank you." Tim asks again, "Hi, Jim! Is this your ruler?" Jim answers, "No, it isn't. It's Tina's ruler." "Is

this your notebook, Jenny?" asks Tim. "Yes, it is," answers Jenny. "Ann, is this your pencil-box?" asks

Tim. "Yes, it is. Thank you." answers Ann.

根据短文内容，判断下列句子正（T）、误（F）。

( )1. Tim, Sonia, Jim, Tina, Jenny and Ann are at home.

( )2. They find a notebook, a pencil, a ruler and a pencil-box on the desk.

( )3. The pencil is Sonia's.

( )4. The ruler is Tim's.

( )5. The notebook is Jenny's.

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单项选择题

生大黄配芒硝属( )

A．相须
B．相使
C．相畏
D．相恶
E．相反
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