一.可否是单射,但不是满射呢?

二.证明恒等式:arcsinx+arccosx=π/2

三.设F(x)和G（x)在[a.b]上连续，在（a,b）内可导，证明在（a,b)内有一点&,使

|F(a)  F（b)|=(b-a)|F(a)  F'(&)|

|G(a)   G(b)|      |G(a)  G'(&)|

四.证明:若函数f(x)在R内满足关系式f'(x)=f(x),且f(0)=1,则f(x)=e的x次

五.甲船以6km/h的速率向东行驶,乙船以8km/h的速率向南行驶,在中午十二点正,乙船位于甲船之北16km,问下午一点正两船相离的速率是多少?(我想请问什么是相离的速率?)

六.计算球体体积时,要求精确度在2%之内,问这时测量直径D的相对误差不能超过多少?

七.注水入深8m上顶直径8m的正圆锥形容器中,其速率为4m3/min.当水深为5m时,其表面上升的速率是多少?

八.lim(ax次+bx次+cx次)x分之一次/3(a,b,c,大于0)

   x-0

 

 

 

 

 

 

 

 

Nowadays,with the rapid development of IT and information industry, cell phones play a dominant role in towns people's life. But, like everything else, they have both favorable and mffavorahle aspects.
    First, it's useful. As a wireless mobile telephone, it's easy and handy to early to wherever one goes and call the callee however far away he is. Therefore, it greatly facilitates people's life. Second, it's convenient. Whenever one meets trouble or something urgent, one can nmke a call immediately. Most important of all, it's a very helpful companion. With a multirfunction cell phone in hand, one can easily get on the Net, browsing the useful information, conducting e-commerce and doing whatever one can do via Internet.
    However, just as everything has two sides, the cell phone also has many disadvantages. To begin with, it's expensive to buy and costly to pay the hills, esp. that of global service. To make matters worse, it's also eas

Population expansion is one of the most serious problems in developing countries. As for many industrial nations, in which the birth rate is lower than the death rate, the problem is not so serious as in developing countries.
    With population increasing,a series of other problems have come up. Land recources, for example, are reducing very fast. According to scientists' estimation, land resources will be exhausted in hundreds of years. Another big problem is that the food supply can not satisfy people's demands. The consequence of these problems will threaten the lives of human beings.
    In order to prevent this terrible consequence, nowadays some of the developing countries have to use fanfily planning to control the birth rate. China, one of these countries, is playing an important role at this point. She made the first family planning program at the beginning of 1980's, and the results are obvious.