搜题请搜索小程序“爱下问搜题”
问题 解答题
讨论y=
1-x2
在[-1，1]上的单调性．
答案

此函数可以看成是由函数y=f（t）=

t
和t=1-x2 复合而成，对于f（t）在t≥0始终单调递增，

对于t=1-x2，在x∈（-∞，-0）上单调递增；在x∈[0，+∞）上单调递减，

有复合函数单调性的“同增异减”法则，可以知道：

当

-1≤x≤1
x∈{x|x＜0}
⇒-1≤x＜0，即当x∈[-1，0）时．函数y=
1-x2
是单调递增函数；

当

-1≤x≤1
x∈[0，1]
⇒0≤x≤1，即当x∈[0，1]时，函数y=
1-x2
是单调递减函数．

单项选择题

第1篇 Food for Learning


In Eritrea, a small country in northeast Africa, approximately 80 percent of the population is illiterate. That percentage is even higher in woman. As in many developing countries, many Eritreans have traditional ideas about the role of women. They believe that women should stay home and take care of the family and should not get an education or look for a job.
These beliefs are one of the factors that prevent Eritriea and other developing countries from improving their economic situation. Experience in many developing countries has shown that educated women have fewer children and have more opportunities for improving their lives and the lives of their families. In Eritrea, in fact, there is great need for improvement. It is one of the poorest countries in the world. For many Eritrean families, getting enough food is a daily problem.
To deal with these problems, the Eritrean government together with the World Food Program, has a new program that offers food as a reward for learning. In primary schools, all the children receive food packages to take home to their families. However, with the new program, the girls receive more food than the boys. This way, parents are encouraged to send their daughter to school rather than keeping them at home.
Another government program that aims to educate women is Food for Training. Managed by the National Union of Eritrean Women, this program offer food rewards (also from World Food Organization) to women and elder girls who are willing to join the program. Because of the war with Ethiopia, many women are bringing up their families on their own. They often live in refugee camps, with no land of their own and no way to earn money. Most of these women are illiterate and have no skills to find a job. They spend most of their day looking for food and preparing it for their families.
The Food for Training program helps the teenagers and women change their lives. If they agree to join the program, they receive a large package of food each month. In return, the women are required to attend free literate classes for two hours every day. When Food for Training classes in two regions of Eritrea, 5000 girls and women joined in the first two months. It is especially popular with teenage girls, aged fourteen to sixteen, who have never had a chance to go to school before.
The organizers of Food for Traing also plans to offer other kinds of courses for women, using the same system of food rewards. In these courses, they will teach women job skills and crafts such as basket weaving. These women will not only learn to read and write. They will become aware of what is going on in their country.

With the Food for Learning program, women get a large package of food as long as ______.

A．they attend free literacy classes every day

B．they have no land of their own

C．they bring up their families on their own

D．they live in refugee camps
查看答案
问答题 简答题

简述希腊悲剧对曹禺戏剧创作的影响。
查看答案