设实数x、y满足x2+(y-1)2=1,令x=cosθy=1+sinθ(θ∈R)

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问题:

设实数x、y满足x2+(y-1)2=1,令
x=cosθ
y=1+sinθ
(θ∈R)
,若x+y+c>0恒成立,求实数c的取值范围.
考点:简单线性规划问题(用平面区域表示二元一次不等式组)圆的标准方程与一般方程圆的参数方程
题型:解答题

阅读理解。

    The Wilsons decided to go overseas for vacation. They had a family meeting to plan the vacation.

    "First," Mr Wilson said, "we should decide where we are going."

    "I don't agree," Mrs Wilson said, "I think we should decide when we are going first. We don't want

to go to places when they are cold."

     Mr Wilson agreed, so the family's first decision was when to go on vacation. They decided to go in

July.

    "Now we can decide where to go," said Mr Wilson.

    "But, Dad," Ben said, "don't you think that where we go depends on (依赖,取决于) how we go? If

we plan to fly, we can go a long way. If we plan to drive, we can't go far."

     Again, Mr Wilson agreed, and they discussed this. At last they agreed to travel by plane.

     And so the planning meeting went on. The next day, one of Mr Wilson's friends at work asked, "Where

are you going for vacation?"

     "Well," Mr Wilson told him, "we are going in summer by plane, but I don't know where we are going!"

根据短文内容回答下列问题。

1. Why did the Wilsons have a family meeting?

                                                                                                                   

2. What did they decide first?

                                                                                                                   

3. When did they decide to go? 

                                                                                                                   

4. How did the Wilsons decide to travel? 

                                                                                                                   

5. What they didn't decide? 

                                                                                                                   

题型:解答题

阅读理解

       My name is Peter. I am 12. I have one brother and one sister. My brother is 15 and my sister is 9.

I have a friend. He is an English boy. His name is Tanaka. He is in my class. I have a dog, too. Its name

is Billy. Billy is 2. I like sports. I play basketball, soccer and volleyball after class(放学后). I have one

pencil case, two English books and three Chinese books.

阅读短文,根据短文内容选择正确答案。

1. Peter has __________.

A. one brother and one sister

B. two brothers and two sisters

C. a Chinese friend    

D. a dog and a cat

2. Billy is __________.

A. Peter's friend      

B. Peter's dog

C. Tanaka's dog      

D. Tanaka's friend

3. —Does peter play sports after class? 

   —__________.

A. Yes, he doesn't.    

B. Yes, he do.

C. Yes, he does.      

D. No, he doesn't.

4. Peter likes ___________.

A. computer

B. balls

C. pens

D. photos

5. Peter and Tanaka are _________.

A. brothers

B. sisters

C. friends

D. Chinese

题型:解答题

智能控制是对档案信息更高程度的控制。智能控制的深化有助于导致实体控制的()。

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依法淘汰( )的化学品,限制生产和使用( )化学品。

A.高毒、难降解、高环境危害,高环境风险
B.高环境风险,高毒、难降解、高环境危害
C.高毒、难降解,高环境危害
D.高环境风险,高环境危害

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什么是频率响应,怎么才算是稳定的频率响应,简述改变频率响应曲线的几个方法?

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