题干

已知函数f(x)满足 f(logax)=
a
a
2
1
(xx1)
(其中a>0,a≠1)

(Ⅰ)求f(x)的表达式;

(Ⅱ)对于函数f(x),当x∈(﹣1,1)时,f(1﹣m)+f(1﹣m2)<0,求实数m的取值范围;

(Ⅲ)当x∈(﹣∞,2)时,f(x)﹣4的值为负数,求a的取值范围.

上一题 下一题 0.0难度 选择题 更新时间:2018-03-21 03:23:34

答案(点此获取答案解析)

解:(Ⅰ)设logax=t,则x=at

代入原函数得, f(t)=aa21<

同类题1

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

How to Enjoy Life As a Teen

    The "best years of your life"? Maybe not, but you can learn to make the most of your high school days.

    Learn to appreciate small things. Whether it's having a computer, having friends, having a good supply of food, a bed to sleep on, family that loves you, having a decent education or simply being born in this world, value it. ____ Be happy, and life will reward you. Remember that these are the last few years you will be able to enjoy yourself without having to worry about the responsibility of an adult, but make sure you prepare yourself for when you do become one. When you actually become an adult, you'll learn to love that responsibility and you probably never want to go back.

    Choose your friends wisely. Unlike what many articles state, you don't have to be popular and have a gazillion friends to be happy. ____ Try to have friends that like you who you are, not just because you are wearing a certain brand of shoes or something like that. These are people who shop at the same store as you; not someone who will sympathize with you when your dog dies.

    Keep your grades up. ____ This also sets you up to get into a college you want to go to, which in turn prepares you for a career you will enjoy, improving your quality of life in the future. You'll get cheap car insurance as well if you have at least a B or A average.

    ____ Participating in clubs, activities, and sports increases your chances of meeting new friends. While you only need 4 or 5 close friends, that doesn't mean you shouldn't try to meet new people. Participating gives you something to do instead of sitting bored at home and wallowing in self-pity.

    Work at a job you can enjoy. Working is a great way co gain experience and to meet other people. ____ This will look great on your resume. If you can't find work, especially in this hard economic time, volunteer or make your own job.

A. Be sociable.

B. Remember the point of life is for you to enjoy it.

C. Find a hobby that is meaningful or practical.

D. In fact, many of the "friends" you have when you are popular are not true friends.

E. When you do get out of college, interviewing companies will look at your previous work experience.

F. Even though you want to enjoy your teen life as best as possible, don't idle away your time in school.

G. There is nothing more satisfying than seeing your hard work pay off in the form of A's and B's (but mainly A's).

同类题3

阅读下面短文,按照句子结构的语法性和上下文连贯的要求,从各题所给的A、B、C和D项中选出最佳选项。

    A long time ago,some farmers lived in a small village.And there was a farmer1 had four sons.

    The farmer raised the four boys on his own.He hoped that his sons could learn not2 opinions about things too quickly.So he gave his four sons 3 question in turn asking them to go to see a pear tree at a distance in different seasons.The sons promised they would not let their father 4.

    The first son5 out in the winter,the second in the spring,the third in the summer,and the youngest in the autumn.

    One year passed.When all of them returned home,the farmer called them together to describe6they had seen.

    The first son said the tree was7bent and distorted.It wasn't worth seeing at all.And it seemed that it wouldn't bear any fruit,8.

    The second son said it was not like that. But the tree was covered9 green buds and made people feel full of hope.

    The third son disagreed,saying that it was full of flowers which smelled so sweet and 10 so beautiful.And he had never seen such beautiful scene that everyone would love it.

    The last son disagreed with all of them,saying that it 11 with fruit,full of life and content.People would be satisfied with it.

    At last,the four sons'eyes were fixed12 their father.The father smiled.Then he told his four  sons that13 they were all correct,they only saw the tree in one season.He told his sons that14 could not judge a tree or a person only by one season,and that the essence of a person could only be measured when all the seasons 15 over.

    If you just give up in winter,you will miss the hope of spring,the beauty of

summer and the harvest of autumn in your life.