题干

函数 y=
1
6
x
x
2
的定义域是____;若函数 f(x)=
6
x
+
b
x
2
+
4
的最大值为
9
4
,则实数 b= ____
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答案(点此获取答案解析)

(3,2),5

同类题1

阅读下面的文言文,完成下列小题。

    程信,字彦实,其先休宁人,洪武中戍河间,因家焉。信举正统七年进士,授吏科给事中也先犯京师信督军守西城都督孙镗击也先失利欲入城信不纳督军从城上发箭炮助之镗战益力也先遂却景泰元年,请振畿辅饥民,复河间学官、生徒因用兵罢遣者,皆报可。明年二月,出为山东右参政,督饷辽东。巡抚寇深奏盗粮一石以上者死,又置新斛视旧加大,属信钩考。信立碎之,曰:“奈何纳人于死!”深由是不悦信。天顺元年,擢太仆卿。京卫马旧多耗,信定期征之。三营大将言太仆苛急,请改隶兵部。信言:“高皇帝令太仆马数,勿使人知。若隶兵部,马登耗,太仆不得闻。脱有警,马不给,谁任其咎?”帝是之,乃隶太仆如故。明年,改左佥都御史,巡抚辽东。都指挥夏霖恣不法,佥事胡鼎发其四十罪,信以闻,下霖锦衣狱。门达言信不当代奏,时寇深方掌都察院,以前邻劾信。征下诏狱,降南京太仆少卿。母忧归。成化元年,起兵部,寻转左侍郎。四川戎县山都掌蛮数叛,陷合江等九县。廷议发大军讨之。以襄城伯李瑾充总兵官,进信尚书,提督军务。至永宁,分道进。信与瑾居中节制。转战六日,破寨七百五十余。前后斩首四千五百有奇,俘获无算。录功,进兼大理寺卿,与白圭同莅兵部。信欲有为,而阻于圭,数称疾。改南京兵部,参赞机务。明年致仕,逾年卒。谥襄毅。

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(节选自《明史·列传第六十》)

同类题2

根据短文理解,选择正确答案。

Coolest Hotels in the World

Ariau Amazon Towers

    The Ariau Amazon Towers hotel lets you sleep in a tree house. Eight towers make up this hotel that offers over 300 rooms. If you really want to get into the spirit, book the Tarzan Suite which is large enough for a big family. You'll be thirty feet up in the air and can travel between the towers through their wooden walkways.

    Prices: starting at $300 one night for each person for a regular room and going all the way up to $3000 for the Tarzan Suite.

    For more information, visit the website: http://www.ariautowers.com

The Ice Hotel

    Every winter in Jukkasjarvi, Sweden, a special kind of hotel called the lee Hotel is built. Each year, world-famous artists are invited to design and produce works of art from the ice, many of which can be found in the rooms. You'll have your choice between hot or cold rooms but you will be well advised to stay at least one night in a cold room for a true experience.

    Prices: starting at $318 one night for each person for either a cold room or a warm one. For more information, visit the website: http://www.icehotel.com

Propeller Island

    Propeller Island City Lodge is a very special hotel that was designed by a German artist. Each room provides you with the possibility of living in a work of art. Every single piece of furniture in the thirty rooms of the hotel has been hand-made and each room is completely different. You'll be able to choose a room based on your own personal tastes.

    Prices: starting at just $91 a night, and an additional person for only 20 extra dollars. For more information, visit the website: http://www.propeller-island.com

    For information about other cool hotels in the world, visit the website: http://www.bahamabeachclub.com