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问题 填空题
过M（1，0）作抛物线y2=8x的弦AB，若|AB|=
8
10
3
，则直线AB的倾斜角是______．
答案

当斜率不存在时，不成立；当斜率存在时，

设直线方程为y=k（x-1），代入抛物线y2=8x得k2x2-（2k2+8）x+k2=0，

设A（x1，y1），B（x2，y2），则x1+x2=

2k2+8
k2
，x1x2=1，

∴|AB|=

(1+k2)(x1-x2)2
=
8
10
3
，

∴k=±

3
∴直线AB的倾斜角是60°或120°．

故答案为60°或120°．

阅读理解

阅读理解。

     Look here ! This is my room. Open the door. You can see two tables. There are some books on

the tables. My keys are on the table, too. Behind the door there is a baseball. I love it very much. On

the wall there are two pictures. Look at the boy. It's me. Where is my football? Oh! It's on the sofa. Is

my computer on the dresser? No, it isn't. It's next to the dresser. What do you think of (认为) my room?

It's very nice, isn't it?

1. There are not any______ in my room.  

A. tables              

B. pictures          

C. basketballs

2. Where are the books ? They're ______.

A. on the sofa          

B. on the wall        

C. on the tables

3. Who is the boy ? It's ______.

A. me                  

B. my brother          

C. my friend

4. Is my football under the sofa?  

A. No, it isn't.          

B.Yes , it is .          

C. I don't  know.

5. Where is my computer ? It's ______.

A. on the dresser        

B. next to the dresser    

C. on the sofa

查看答案
多项选择题

在借贷记账法下，期末有余额的账户类别是（）账户。

A.资产类

B.损益类

C.负债类和所有者权益类

D.成本类
查看答案