问题 填空题
双曲线x2-
y2
4
=1
的焦点到渐近线的距离等于______.
答案

由题意可得双曲线x2-

y2
4
=1中,

a=1,b=2,c=

1+4
=
5

故其焦点为(±

5
,0),

渐近线方程为y=±

b
a
x=±2x,

不妨取焦点(

5
,0),渐近线y=2x,

由点到直线的距离公式可得:

所求距离d=

|2
5
-0|
22+(-1)2
=2

故答案为:2

填空题
阅读理解

Last winter vacation, our class went to Xiangshan for a trip.Though the weather was a little cold, it was sunny.

At six in the morning we met at the school gate.We took a bus there.On the bus, our monitor told us an interesting story.The story was about an interesting man.Then three girls in our class sang songs.We were very happy.

At about seven thirty we got there.It was a beautiful mountain.There were many visitors.Then we started to climb the mountain.The boys had a climbing race(比赛).Li Ming won the first prize.He got a blue hat.At about nine o’clock we met a famous singer.Qi Hui and Ma Yan even got his autographs.They were very excited.

We had lunch in the mountain.We brought food from home and ate together.

After lunch we went to the zoo, because the was a new member(成员) in the zoo.It was a cheetah(猎豹).It came from Africa.

Finally, we took the bus back to school.Although we were tired, we really had fun.

小题1:How was the weather on that day?

A.It was warm and sunny.

B.It was hot and sunny.

C.It was cold, but sunny.

D.It was cold and cloudy.小题2:They went to the mountain       .

A.by bike

B.by bus

C.on foot

D.by car小题3:It took them about       to get to he mountain.

A.one and a half hours

B.an hour

C.forty minutes

D.half an hour小题4:They had lunch       .

A.at home

B.at school

C.in a restaurant

D.in the mountain小题5:Which of the following is TRUE according to the passage?

A.They were quiet on the bus.

B.Two students got the singer’s autographs.

C.They bought food in the mountain.

D.The cheetah came from America.