题干

已知抛物线y=ax2+bx+c的开口向上,顶点坐标为(3,﹣2),那么该抛物线有(  )


A:最小值﹣2  

B:最大值﹣2

C:最小值3

D:最大值3

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答案(点此获取答案解析)

A

同类题2

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    Palema Malhotra and her husband Anil Malhotra have spent the last 25 years buying the waste agricultural land and reforesting it, to return the land to a bio – diverse rainforest for elephants, birds and other creatures.

    The couple owns 300 acres of land in Brahmagiri, India. They have spotted more than 300 kinds of birds as well as many rare and threatened animal species. But, this was not the scene in 1991 when Anil and Pamela came to this part of the country. “When I came here, it was a wasteland. The owner wanted to sell because he couldn't grow coffee or anything else,” says Anil who worked in the real estate(房地产)and restaurant business in the US before moving to India. “For me and Pamela, this was what we were looking for all our life.”

    The couple had a love for nature from their childhood. When the Malhotras came to India, the pollution horrified them. “That was when we decided to do something to reclaim(开垦)the forest in India,” says Anil. “We were not looking for money. Early on, we realized that shortage of fresh water will be a concern for India and the rest of the world. Acquisition, protection and reclamation of forested lands and wildlife habitat, where vital water sources have their origin, is the only way to save ourselves,” explains Anil.

    They sold what they owned in America, bought the first 55 acres and began to grow a forest. Soon they bought the land nearby as well. “Many of the farmers considered their holdings 'wasteland' as very little grew on it and were happy to get money,” says Anil.

    Hunting and poaching(偷猎)was a challenge and often the locals did not understand what this couple was doing, so it required a lot of talking to create awareness. They worked with the forest department to set up camera traps and keep poachers away. “There are times I have fought with poachers,” says Pamela.

同类题4

阅读下面的文字,完成后面小题。

善借者赢天下

王飙

       ①人生有涯,事业无疆。怎样才能利用有涯的人生岁月,在无疆的事业中纵横驰骋成为英雄呢?聪明的犹太人有一句名言:借别人的鞋子比打赤脚跑得快!他们在世界多个领域一直都是领跑者,占尽了先机和风流。因为他们懂得:一个人的能力是有限的,仅靠自己的单打独斗,也许自食其力不成问题,但若想获得突破性的发展,恐怕就力不从心了。所以,唯有善借者,才能从平凡走向卓越,从贫穷走向富贵,从卑微走向伟大。

       ②丹尼尔·洛维洛是美国有名的亿万富翁。其实,他孤身奋斗拼搏到了近40岁的时候还是个穷人,成为船主的梦想还是镜花水月,前途一片暗淡。然而,有一天他突然来了灵感:何不借银行的钱筑自己的梦呢?当时正有一艘旧货船出售,他成功地说服了一家银行,以这艘旧货船作抵押贷款,买下后将之改为油轮包租出去。随后,他又到银行借到另一笔贷款,买了第二艘货船,将之改成油轮出租。几年之后,他靠“借”拥有了自己的船队;也是靠整个 “借”字,他获得了滚雪球式的发展,最终登上了世界船王的宝座。丹尼尔以“借”来成就自己梦想的智慧,连奥纳西斯和尼亚斯这两位大名鼎鼎的希腊船王也自叹不如。

       ③其实,借的艺术和智慧,在我们这个古老的国度里,可谓花开烂漫,果实累累。先秦时期的荀子就写道:“假舆马者,非利足也,而致千里;假舟楫者,非能水也,而绝江河。”“假”的意思便是“借”。纵观世界,我们可以看到,凡是能取得天下者,莫不是善借之人,其中最有代表性的人物应该是刘邦。一个白手起家的亭长,最终登上了皇位,之后他说了一段意味深长的话:“夫运筹策帷帐之中,决胜于千里之外,吾不如子房;镇国家,抚百姓,给馈饷,不绝粮道,吾不如萧何;连百万之军,战必胜,攻必取,吾不如韩信。”刘邦正是借助这三人超凡卓绝的智慧,最终取得了天下,“此三者,皆人杰也,吾能用之,此吾所以取天下也。”试想:仅靠刘邦一人之力,他是项羽的对手吗?而此三子虽为人中豪杰,但若不借助刘邦宏伟远大的理想抱负、宽广如海的气度胸怀和高妙超逸的用人智慧,那么,在中国的历史上也很难成就自己的宏业伟绩。

       ④曹雪芹在《红楼梦》里借薛宝钗之口说:“好风凭借力,送我上青云。”人生在世,谁不渴望像丹尼尔那样成就自己的梦想?谁不渴望像刘邦那样铸就辉煌的人生?成功的港湾是美丽的,也是人人向往的。你要善于借助外在的力量,让自己理想的航船到达成功的彼岸。庄子有言:“鹏之徙于南冥也,水击三千里。抟扶摇而上者九万里,去以六月息者也。”意思是说,大鹏鸟往南方的大海迁徙的时候,翅膀拍打水面,能激起三千里的浪涛,环绕着旋风飞上了九万里的高空,乘着六月的风离开了北海。因此,不管你是“借鸡生蛋”,还是“借风腾云”;也歹

       ⑤管你是“借水行舟”,还是“借力打力”;更不管你是“猛虎借山”,还是“蛟龙借海”,只要你借得巧妙,借得聪明,自然就能借来人生事业的风生水起,借来平生抱负的宏图大展。

(选自《思维与智慧》2016年第6期,有改动