题目

曲线在点处的切线方程为__________________ 答案：3x+y-2=0 【解析】因为，所以， 曲线在点处的切线的斜率为：， 此处的切线方程为： 点睛：曲线y＝f(x)“在点P(x0，y0)处的切线”与“过点P(x0，y0)的切线”的区别：前者P(x0，y0)为切点，而后者P(x0，y0)不一定为切点． 阅读理解 　　There was a man who had a little son．He loved him very much．Every day after work the man would come home and play with the little boy． 　　When the man came home from work one night, he found that he had some extra work to do．And he wasn't able to play with his little son, He wanted to give the boy something to keep him busy．So, looking around his study, he saw a magazine with a large map ot the world on the cover．He got an idea He patiently tore the map up into pieces．Then he led his son into the dining room and spread the pieces on the table．He explained to the boy that it was a map of the world．He told the boy to put it back together and they could play together when he finished．Surely this could keep the child busy for hours, he thought． 　　After about thirty minutes, the boy came to the man and said, ""Okay, it's finished, Dad．Can we play now?" 　　The man was surprised, saying, "That's amazing! How did you do that?" The boy said," It was easy．On the back of the page was a picture of a man．When I put the man together, the whole world appeared completely．" (1) Why couldn't the man play with his son that night? [　　] A． He had to read a magazine． B． He had some extra work to do． C． He had to learn something about a map． D． He had to stay at his office for extra work． (2) What did the man ask his son to do? [　　] A． To read the magazine to find the map． B． To tear the map of the world up into pieces． C． To put the pieces of the map of the world back together． D． To clean the dining room first, and then read the map of the world． (3) How long did it take the boy to finish the work? [　　] A． A few hours． B． About an hour． C． About half an hour． D． The whole night． (4) Which of the following is TRUE about the passage? [　　] A． It's a report about a father's extra work． B． It's a story between a father and his clever son． C． It's an advertisement for the map of the world． D． It's a poster about how to deal with parents' problems．