热点试题

[ 数学 ] 甲容器有5%的盐水800克,乙容器有10%的盐水200克.先分别从甲和乙中取出相同重量的盐

甲容器有5%的盐水800克,乙容器有10%的盐水200克.先分别从甲和乙中取出相同重量的盐水,再把从甲中取出的倒入乙中,把从乙中取出的倒入甲中,现在两种容器中的盐水的浓度相同.问:分别从甲和乙中取出盐水多少克?

2016-05-17 | 0

[ 数学 ] 不论为何值,代数式的值( )A.总不小于7B.总不小于2C.可为任何有理数D.可能为负数

不论为何值,代数式的值(   )
A.总不小于7B.总不小于2C.可为任何有理数D.可能为负数

2016-05-17 | 0

[ 数学 ] 如果二次函数y=ax2+m的值恒大于0,那么必有( )A.a>0,m取任意实数B.a>0,

如果二次函数y=ax2+m的值恒大于0,那么必有(  )
A.a>0,m取任意实数B.a>0,m>0
C.a<0,m>0D.a,m均可取任意实数

2016-05-19 | 0

[ 数学 ] 在△ABC中,∠ACB=90°,∠BAC=30°,将△ABC绕顶点C顺时针旋转,旋转角为θ

在△ABC中,∠ACB=90°,∠BAC=30°,将△ABC绕顶点C顺时针旋转,旋转角为θ(0°<θ<180°),得到△A′B′C.
(1)如图1,当A′B′AC时,设A′C与AB相交于点D.证明:△BCD是等边三角形;
(2)如图2,连接A′A、B′B,设△ACA′和△BCB′的面积分别为S△ACA′和S△BCB′.求:S△ACA′与S△BCB′的比;
(3)如图3,设AC中点为E,A′B′中点为P,BC=a,连接EP,求:角θ为多少度时,EP长度最大,并求出EP的最大值.

2016-05-20 | 0

[ 数学 ] 已知:如图,在△ABC中,点D,E分别在AB,AC上,连接DC,BE,若∠BDE+∠BCE

已知:如图,在△ABC中,点D,E分别在AB,AC上,连接DC,BE,若∠BDE+∠BCE=180°.

(1)写出图中两对相似三角形(注意:不得添加字母和线);
(2)请你在所找出的相似三角形中选取一对,给予证明。

2016-05-20 | 0

[ 数学 ] 要考查一个学生小学一年级到六年级的学习成绩进步情况,采用的统计图比较合适的是 [    

要考查一个学生小学一年级到六年级的学习成绩进步情况,采用的统计图比较合适的是[    ]
A.条形统计图
B.扇形统计图
C.折线统计图

2016-05-21 | 0

[ 数学 ] 定义={z|z=xy+,x∈A,y∈B},设集合A={0,2},B={1,2},C={1}

定义={z|z=xy+,x∈A,y∈B},设集合A={0,2},B={1,2},C={1},则集合的所有元素之和为[    ]
A.3
B.9
C.18
D.27

2016-05-21 | 0

[ 英语 ] 阅读理解。     Welcome to order (订购) Healthy-food

阅读理解。
    Welcome to order (订购) Healthy-food Basket. It's only $87. Healthy-food Basket is a good
present for your friends and family. You can send it to them on special (特殊的) days or on any day!
There is fresh fruit, cookies, juice and water in the basket. To order the basket, you can:
     ●Call Mr. Smith at 586974
     ●Send an e-mail to healthy-food basket @ yahoo. com.
1. How much is Healthy-food Basket? It's ________.
A. $ 78        
B. $87          
C. $98          
D. $76.
2. You can't find ________ in the basket according to (根据) the passage.
A. some fruit
B. some cookies
C. some vegetables
D. some juice
3. You can order the basket by ________.
A. writing a letter
B. calling Mr. Smith at 586974
C. sending an e-mail          
D. B and C

2016-05-28 | 0

[ 英语 ] The twins are so much alike that it is diffic

The twins are so much alike that it is difficult to tell one from________.
A.otherB.the otherC.othersD.another

2016-05-28 | 0

[ 英语 ] —Maybe Jim can’t go to the park tomorrow .He

—Maybe Jim can’t go to the park tomorrow .He is ill .
—If he doesn’t go , ______.
A. neither do I  B. neither will I   C. so will I

2016-05-28 | 0