辽宁号航母纪念章从2012年10月5日起开始上市.通过市场调查,得到该纪念章每1

题型:解答题

问题:

辽宁号航母纪念章从2012年10月5日起开始上市.通过市场调查,得到该纪念章每1枚的市场价y(单位:元)与上市时间x(单位:天)的数据如下:
上市时间x天41036
市场价y元905190
(1)根据上表数据,从下列函数中选取一个恰当的函数描述辽宁号航母纪念章的市场价y与上市时间x的变化关系:①y=ax+b;②y=ax2+bx+c;③y=alogbx;
(2)利用你选取的函数,求辽宁号航母纪念章市场价最低时的上市天数及最低的价格;
(3)设你选取的函数为f(x),若对任意实数k,方程f(x)=kx+2m+120恒有两个相异的零点,求m的取值范围.
考点:函数解析式的求解及其常用方法
题型:解答题

Dogs can also go to school to learn how to help people who cannot hear. If a person cannot hear, we say he or she is deaf.

Dogs who help deaf people must learn many different sounds. Then they must be able to show the deaf person what is making the sound. When they hear a visitor at the door, dogs learn to walk to the deaf person and then walk to the door. And if a telephone rings, they walk to the deaf man or woman and then walk to the telephone. These dogs can also help deaf mothers. If a baby is crying in another room, dogs walk to the mother and then to the baby. These dogs wear a yellow coat to show that they are special dogs that are helping a deaf person. There have been many times when these dogs have saved a life. You may see in a newspaper that a dog heard a fire alarm and lay down near the deaf person's feet. That is the sign for danger. The person knows that something is wrong and can go away from the fire.

Special dogs can also help people who are disabled in various ways. For example, dogs can pull off their gloves or socks! Think how difficult your life would be if you were blind, deaf or disabled! But if you had a special dog like this to help you, your life would be much easier.

小题1:Dogs who help deaf people must learn             

A.different sounds

B.different languages

C.different colors

D.different faces小题2:According to the passage, the special dogs can NOT             

A.care for babies

B.talk to people

C.realize the danger

D.pull off socks小题3:Which of the following statements is TRUE?

A.Special dogs can do what people cannot do.

B.Special dogs can only help people who are deaf.

C.Special dogs can help people in every part of their life.

D.Special dogs can make some people's life much easier.

题型:解答题

在2、27、47、58、95、33、70、11这些数中,______是质数,______是合数.

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对于HSD检验和Scheffe检验,以下哪种说法是错误的( )

A.两种检验都是事后检验

B.HSI)检验比Scheffe检验更敏感

C.HSD检验只能用于n相等的情况

D.Scheffe检验控制了族系(familywise)误差,因此犯Ⅰ类错误的风险较小

题型:解答题

USB接口只能连接U盘。

题型:解答题

武警边防部队执勤及生活补助费的管理遵循()的原则

A、来源合理

B、统筹兼顾

C、先收后支

D、公平适度

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