已知集合A={x||1-x-13|≤2}；集合B={x|x2-2x+1-m2≤0_爱下问搜题

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问题解答题

已知集合A={x||1-

x-1

3

|≤2}；集合B={x|x2-2x+1-m2≤0}的解集，若C_RA是∁_RB的必要不充分条件；
求：
（Ⅰ）集合A，B；
（Ⅱ）实数m的取值范围．

答案

（Ⅰ）由|1-

x-1

3

|≤2得：-2≤

x-4

3

≤2，

∴-2≤x≤10，

∴A=[-2，10]；

∵x²-2x+1-m²=[x-（1-m）][x-（1+m）]≤0，

∴当m≥0时，B=[1-m，1+m]；

当m＜0时，B=[1+m，1-m]；

（Ⅱ）∵C_RA是∁_RB的必要不充分条件，

∴B是A的必要不充分条件．

∴当m≥0时，A=[-2，10]⊆B=[1-m，1+m]；

即

1-m≤-2

1+m≥10

m≥0

∴m≥9；

当m＜0时，A=[-2，10]⊆B=[1+m，1-m]；

同理可得，m≤-9．

写句子

我会按要求改写句子。

1．难道我们不该珍惜时间，努力学习吗？（改为陈述句）

2．机灵的小松鼠在树上高兴地跳着叫着。（缩句）

3．小姑娘把水罐交给了母亲。（改“被”字句）

4．下课后，我被老师叫到了办公室。（改“把”字句）

5．白云飘来飘去。（扩句）

完形填空

I went to India for a 2-week vacation to visit my relatives, We stopped on a red light, and as always, there was a lot of activity outside the cars near the     . People walked in, between the cars       newspaper. water and a number of kids looked for a bit of charity from the car owners. It' s a familiar      in most poor developing' countries.
While we were   for the red light to turn green, I noticed a man outside a couple of    in front of ours trying to sell bottles of water. It's      unusual at first. He was a man in his 40s with relatively    clothes. But he walked around in a strange way. He kind of     his way around the spaces. He was blind.
Carrying a couple of water bottles on one hand, he    got to the outside of our car. Out of     , my mum decided to buy one water bottle. As she gave the man the money, the light turned green. The car behind sounded loudly and     , trying to get ahead of traffic. Seeing this, my mum kindly told the man to     the change. However, with his-superior sense of touch, he quickly      his shirt pocket and threw the money at my mum's      . It was the exact change. T he cars behind us were really getting out of control,       we decided to go on our way.
I      and even cried when I got home. Here's a blind man, born in       ,trying to sell water bottles on the streets to make ends meet. He      our sympathy. Life hasn't been      to him, yet he's giving it his best shot. I think that is what       is all about . facing life bravely.

B．fashionable

A．impatiently

A．searched for

B．went through

C．turned over