题干

已知函数f(x)=
2
x
+
b
2
x
+
a
,是定义在R上的奇函数.

(Ⅰ)求函数f(x)的解析式;

(Ⅱ)求函数f(x)的值域.

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答案(点此获取答案解析)

解:(Ⅰ)f(x)在R上的奇函数,f(0)=0,得b=﹣1,

∴f(x)=

又∵f(﹣x)=﹣f(x),

同类题3

阅读下文,回答问题

幸福很小

    朋友买了一间房,面积不大,八十个平方不到。而且是尾房,房间布局不(合适  合理),采光也不是很好。

    我去玩时,朋友和他的太太把我带到露台上。我看到露台上放了一张桌子,还有一些休闲椅。朋友把水果、瓜子从房里搬出来,还给我泡了茶。我坐在阳光里,微风轻拂,惬意极了。朋友的太太在给一些刚绽了骨朵的花儿浇水,她指着不远处操场上的孩子们说:“那儿是个幼儿园,你看这些孩子,玩得多开心啊!”

    朋友的太太站在露台上,看着那些孩子,笑意融融的。

    从朋友家回来,我似乎知道朋友为什么要买下这间房子了。一个在都市之中,还能读懂孩子,还能从孩子那儿感受快乐的人,他肯定是一个能把握住幸福的人。即使这样的幸福很小,小得可以(忽略  忽视)不计,但他们(竟然  仍然)把它牢牢抓在了手里。

    还有位朋友,在杭州一家贸易公司上班,收入并不高。大家都劝他换一份工作,但是他却在那家公司一呆就是十年。

    说起原因,真的让人不敢相信。朋友的家在郊区,为了每天能回去,他五年前就购了一辆车,每天上下班有三个小时在路上。之所以不愿离开那家单位,是因为这家公司有足够的车位,不论他何时到达,车位总不会被停满。

    他(竟然  仍然)是为了一个车位,宁愿放弃其他更好的就业机会,让人百思不得其解。但他却没有认识到自己的决定是错误的,相反,他的日子过得安安稳稳的。他喜欢过这种工作在城里,居家在郊区的日子,你能说他不快乐、不幸福吗?

    生活是有秘密的,如果你没有接近一个人的心灵和情感,你就不会发现这一切。原来你以为他们那种是枯燥、毫无乐趣的生活,其实,根本不是你想象的那样。

    幸福很小.如果你的心很大,那么幸福就擦肩而过了。

同类题5

阅读下面短文,掌握其大意,然后从每题所给的A、B、C、D四个选项中选出最佳选项。

    My six-year-old daughter, Cindy, and I stopped at a food shop for some bread. As we were going out of the door, a young teenage boy was coming in.

    The boy had a strange hairstyle. His nose was pierced, and a ring ran 1 the hole. He held a skateboard under one arm and a2 under the other.

    Cindy, who was walking ahead of me, suddenly 3 when she saw the boy. I thought he had frightened my daughter. But I was 4. My daughter backed up against the door and opened it as wide as it would go. Now I came face to face with the young man. I 5 aside (到一边) and let him pass. He replied vey 6, “Thank you very much.”

    On our way to the car, I praised Cindy for holding open the door for the boy. It seemed that she was not troubled by the boy's appearance,7 I still wanted to make sure. I wanted to be ready to talk about the young man 8 was so different from others.     I prepared to tell my little daughter what 9should be like.   

    But as it turned out, the person who needed the talk was 10!

    The only thing Cindy noticed about the boy was the fact that his arms were 11. “ He held a skateboard under one arm and a basketball under the other. He would have a 12 time to open the door,” said Cindy.

    I just 13  the hairstyle, the piercing and the ring, while she saw a person carrying something under arms and heading towards a(an)14 door.

    What my daughter said 15 me that I should change my ways of judging people and learn from my daughter to be open-minded and warm-hearted.