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下面三个集合：①{x|y=x2+3x﹣2}，②{y|y=x2+3x﹣2}，③{（x，y）|y=x2+3x﹣2}．
（1）它们是不是相同的集合？
（2）它们的区别在哪里？

已知集合H是满足下列条件的函数f（x）的全体：在定义域内存在实数x0，使得f（x0+1）=f（x0）+f（1）成立．
（1）幂函数f（x）=x﹣1是否属于集合H？请说明理由；
（2）若函数g（x）=lg∈H，求实数a的取值范围；
（3）证明：函数h（x）=2x+x2∈H．

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①我国的人民民主具有真实性 ②人民当家作主的权利有物质保障
③我国的人民民主具有广泛性 ④人民当家作主的权利有法律保障
A．①② B．①④ C．②③ D．③④

cosα+2sinα=-根号5，则tanα=

数学题不会啊！！！求解析！！

诸暨市就“全国文明城市创建”公开征求意见，问计于民。社会各届人士以强烈的主人翁意识踊跃参与，纷纷通过电子邮件、信件和教育部门户网站等多种渠道发表意见和建议。不到一个月时间，市政府就收到2000多条建议。经过认真研究，很多合理性的建议被政府采纳。这对全国文明城市创建起到了积极的作用。
用“民主决策”有关知识分析，该市就“全国文明城市创建”公开征求意见，问计于民做法的意义。

我国公民在法侓上

1、（单选）如图所示半球形碗放在水平地面上，过碗内上A点半径与竖直方向
夹角为300
，要想使质量为m的光滑小球静止在碗内的A点，对小球施加一推力的
作用则推力的最小值为（）
ABCD

Some students wish that they could always see the smiles on their teachers’ faces.　1　 Why do teachers seldom smile,especially in class? 
I believe all the people,including teachers,want to smile in their daily life.Teachers teach us from morning till evening every day,which is very difficult.It is because of teachers’ hard work that we students can know a lot about different fields.Nevertheless,some students don’t study hard,which makes teachers unhappy.　2　  
What’s more,other students don’t listen carefully in class.Instead,they sometimes talk,make faces,look outside or do some other things not related to their study.They don’t work hard,and often make teachers angry.Can teachers smile in these cases?Of course not.　3　  
The first and most important thing is that you must put your heart and mind in your study.That means you should listen to your teachers carefully in class.Try your best to grasp what is taught in class.
　4　 If you have any difficulty,you can turn to your teachers or classmates for help. 
Last but not least,try to talk with your teachers in your free time.Also,when your teachers are ill,they need your care.Some of your words may make them smile.
　5　 
A.As a result,teachers can’t wear smiles on their faces.
B.If you can do as I tell you to,your teachers will then often smile.
C.In my opinion,if you want to make teachers smile,you must do the following things.
D.However,instead of the smiling faces,they usually see the cold,even freezing faces of teachers.
E.Smiles are of great importance to not only us but also our teachers.
F.Second,go over what you have learned after class and finish your homework on time.
G.Remember to smile at life however hard it is.

求助

求大神

请输入问题描述，也可上传图片，问题内容越详细，答案就会越准确

数学必修5

1.设为小于的角，为第一象限角，则等于
A. 为锐角 B. 为小于的角
C. 为第一象限角 D.

一篇作文，很急，求哥哥姐姐们帮忙写一篇，拜托了

设a，b∈R，集合{1，a+b，a}＝{0，，b}，则b﹣a＝（　　）
A．1 B．﹣1 C．2 D．﹣2

已知函数f（x）的定义域为（﹣1，0），则函数f（2x+1）的定义域为（　　）
A．（﹣1，1） B． C．（﹣1，0） D．

已知集合A＝{1，3，}，B＝{1，m}，A∪B＝A，则m的值为（　　）
A．0或 B．0或3 C．1或 D．1或3