问题 解答题

已知二次函数f(x)=ax2+bx,﹣1≤f(﹣1)≤1,3≤f(1)≤5.

(1)求a,b的取值范围;

(2)求f(2)的取值范围.

答案

解:(1)因为﹣1≤f(﹣1)≤1,3≤f(1)≤5.

所以 

所以1≤a≤3;1≤b≤3;

(2)因为f(2)=4a+2b,

4a+2b=(a﹣b)+3(a+b),

因为 

所以8≤(a﹣b)+3(a+b)≤16,

即8≤f(2)≤16.

阅读理解

Pingyao is one of China’s three protected ancient cities (the other two are Xi’an and Jingzhou). Lying in the middle of Shanxi Province, 90 kilometers south of Taiyuan, Pingyao ancient city used to be about two hours’ drive from the capital of Shanxi Province, but now the distance is only one hour and ten minutes’ drive after the highway was built. With a history of over 2,700 years, the ancient city stands out as one of the best protected of all the walled cities in China.

On December 3rd, 1997, UNESCO (联合国教科文组织) added Pingyao to the World Heritage (遗产) List as a world’s culture heritage. According to the UNESCO World Heritage Commission(委员会),the Pingyao ancient city is a wonderful example of the Chinese Han cities during the Ming and Qing dynasties. All the features of the Pingyao ancient city have been protected, and it shows an outstanding Chinese historical development including its culture, society, economy and religion(宗教信仰).

根据短文,从题中所给的A、B、C、D四个选项中,选择最佳答案。(10分)

小题1:How many preserved ancient cities are there in China?

A.One.

B.Two.

C.Three.

D.Many.小题2:Why is Pingyao one of the ancient cities?

A.Because it is a wonderful example of the Chinese Han cities.

B.Because it has a history of over 2,700 years.

C.Because all its features have been preserved.

D.Because it includes its culture, society, etc.小题3:It will take you about one hour to get to Pingyao from Taiyuan ______ .

A.by plane

B.by bike

C.by train

D.by car小题4:Pingyao is a wonderful example of the Chinese Han cities during the ______ and ______ dynasties.

A.Yuan; Qing

B.Ming; Qing

C.Song; Yuan

D.Song; Ming小题5:If you go there some day, you shouldn’t ______ .

A.carve your name on the wall

B.draw a picture on the wall

C.litter everywhere

D.destroy the city

单项选择题 共用题干题