
(a、b∈R,a、b为常数),且y=f(x)在x=1处切线方程为y=x﹣1.(1)求a,b的值;
(2)设h(x)=
, k(x)=2h′(x)x2 , 求证:当x>0时,k(x)<
+
.
| 学号 | 姓名 | 到校时间 | 离校时间 | 状态 |
| 2020050101 | 陈芸 | 2021/5/10 6:50 | 2021/5/10 11:55 | 正常 |
| 2020050903 | 刘晓东 | 2021/5/10 6:54 | 2021/5/10 10:55 | 异常 |
| 2020050324 | 钱宇 | 2021/5/10 7:13 | 2021/5/10 10:55 | 异常 |
| 2020050903 | 刘晓东 | 2021/5/10 13:13 | 2021/5/10 17:02 | 正常 |
| …… | …… | …… | …… | …… |

①用稀HNO3清洗做过银镜反应实验的试管
②制取乙酸乙酯时应用饱和NaCl溶液吸收生成的乙酸乙酯
③不慎将苯酚溶液沾到皮肤上,立即用酒精淸洗
④实验室制取乙烯时应将温度严格控制在140℃
⑤苯酚遇到FeCl3溶液会变蓝色
⑥配制浓硫酸和浓硝酸的混合酸时,将浓硫酸沿器壁慢慢加入到浓硝酸中,并不断搅拌
,则
.
Fires do happen. If there is a fire, you might not have much time to decide what to do. Being prepared and knowing what to do early can save your life. Your family should practice this getting﹣out plan. If you have such a meeting place outside, you can quickly make sure that everyone is out of the house.
You should also remember that smoke is usually far more dangerous than the fire. A person can die after just a few minutes in a smoke filled room.
Finally, before you open any doors, always feel the door lock first. If the door lock is hot, fire must be on the other side of the door. You will have to find another way out. These are simple suggestions..
A. Your family should also have a meeting place outside. B. The most important thing is to have a getting-out plan. C. Since smoke rises, stay low to the floor. D. Go upstairs to the top of the building. E. If you can remember them, you will be much safer in a fire. F. Do not open it! G. Can you use water to put out the fire? |
Lisa:Hey,Jane.
Jane:Really?
Lisa:Yeah,it's a dancing party.
Jane: .
Lisa:Do you want to go with me?
Jane:Can I?I don't really know Susan.
Lisa: She said I could invite a friend.
Jane:OK,then.I'd love to go. .
Lisa:On Saturday night.
Jane:Wow,that's the day after tomorrow ! I need to get a new dress.
Lisa: .There's a clothes shop near here. Let's go there after work.
Jane:Sounds good!
“尼摩船长,”我说,“这支枪十分好,并且便于使用。我现在真想试试它。不过我们怎样到海底下去呢?”
“教授,此刻诺第留斯号搁浅在海底下十米深处,我们只待动身出发了。”
“我们怎样出去呢?”
“您不久就知道。”
—It's twenty _____five now .
