已知函数在R上满足，则曲线在点处的切线方程是

A．         B．      C．         D．

（本题14分）设

（1）当时，求在处的切线方程；

（2）当时，求的极值；

（3）当时，求的最小值。

假如英语课上老师要求同学们交换修改作文，请你修改你同桌写的以下作文，文中共有10处语言错误，要求你在错误的地方增加、删除、或修改某个单词。
增加：在缺词处加一个漏字符号（^），并在其下面写上该加的词。
删除：把多余的词用斜线（＼）划掉。
修改：在错词的下面划一横线，并在该词下面写上修改后的词。
注意：
1．每次错误以及修改均限一词；
2．只允许修改10处，多者从第十一处起不计分。例如：
The temple stands nearby the city. It dated from 1961 and is 50 meters in high. It is one of the most famous temple in the country and about 5,000 tourists  come to visit every year. Five years ago, people decided to repair the temple, but this work was completed last year. The ground floor has been complete painted, and the roof, too. All the rooms has been protected from birds by fixed wires across the windows. Trees and flowers have been planted around the temple. We believe, in a few years, the temple will take on new look. 

此题要求改正所给短文中的错误。对标有题号的每一行作出判断：如无错误，在该行右边横线
上画一个勾（√）;如有错误（每行只有一个错误），则按下列情况改正：
该行多一个词：把多余的词用斜线（\\)划掉，在该行右边横线上写出该词，并也用斜线划掉。
该行缺一个词：在缺词处加一个漏词符号（∧)，在该行右边横线上写出该加的词。
该行错一个词：在错词的下面画一横线，在该行右边横线上写出改正后的词。
注意：原行没有错的请不要改。

请你修改以下作文，文中共有10处语言错误，要求你在错误的地方增加、删除、或修改某个单词。
增加：在缺词处加一个漏字符号（^），并在其下面写上该加的词。
删除：把多余的词用斜线（＼）划掉。
修改：在错词的下面划一横线，并在该词下面写上修改后的词。
注意：
1．每次错误以及修改均限一词；
2．只允许修改10处，多者从第十一处起不计分。
Li Ming and Li Juan study very hardly. They do extremely well all the subjects. Li Juan decides to attend in Sichuan University while Li Ming preferred Beijing University. It makes them differ from the most students is that they don’t go to school. In fact, they have never been to school. Since kindergarten, we have studied at home. Neither of them feels they have missed anything by taught at home all the time. Like many people received home schooling in Chengdu, and they feel they are lucky.