题目
题型:不详难度:来源:
①从总体中抽取样本(x1,y1),(x2,y2),…,(xn,yn),若记
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063420-79317.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063420-42251.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063421-45720.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063421-53169.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063421-54457.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063420-79317.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063421-45720.png)
②将函数y=cos 2x的图象向右平移
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063421-77934.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063422-33809.png)
③已知数列{an},那么“对任意的n∈N*,点Pn(n,an)都在直线y=2x+1上”是“{an}为等差数列”的充分不必要条件;
④命题“若|x|≥2,则x≥2或x≤-2”的否命题是“若|x|≥2,则-2<x<2”.
答案
解析
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063421-77934.png)
y=cos 2
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063422-47171.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063422-28366.png)
=cos
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063423-25882.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063423-44736.png)
=sin
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063422-33809.png)
核心考点
试题【给出以下四个命题,所有真命题的序号为________.①从总体中抽取样本(x1,y1),(x2,y2),…,(xn,yn),若记=,=i,则回归直线必过点(,)】;主要考察你对四种命题等知识点的理解。[详细]
举一反三
①“直线a∥直线b”的充要条件是“a平行于b所在的平面”;
②“直线l⊥平面α内所有直线”的充要条件是“l⊥平面α”;
③“直线a,b为异面直线”的充分不必要条件是“直线a,b不相交”;
④“平面α∥平面β”的必要不充分条件是“α内存在不共线三点到β的距离相等”.
其中正确命题的序号是( )
A.①② | B.②③ | C.③④ | D.②④ |
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063351-41923.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063351-12791.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063351-64958.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063351-74660.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063351-13513.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063352-87757.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063352-81000.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063352-51483.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063352-60402.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063352-29503.png)
①若
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063352-15767.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063353-64545.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063353-70452.png)
②若
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063352-15767.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063353-19797.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063353-16287.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063354-69367.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063354-37777.png)
③若
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063352-15767.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063353-19797.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063354-52398.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063354-47680.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063354-69367.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063354-63553.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063355-57561.png)
④若
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063352-15767.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063353-19797.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063354-52398.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063354-47680.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063354-69367.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063354-63553.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191102/20191102063355-41342.png)
A.“若![]() ![]() |
B.“![]() ![]() |
C.“![]() ![]() ![]() ![]() |
D.“![]() ![]() |
A.若|z1-z2|=0,则![]() ![]() |
B.若z1=![]() ![]() |
C.若|z1|=|z2|,则z1·![]() ![]() |
D.若|z1|=|z2|,则![]() ![]() |
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