1 . 已知复数
(
).
(1)若
是纯虚数,求
的值;
(2)若
在复平面内对应的点在第四象限,求
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a2f207a0e5afc530a25ae2dec1499e5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dcd9218a657b17654c5d757a6f7dee9a.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e81e59019989b7dc2fb59b037ef6e010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e81e59019989b7dc2fb59b037ef6e010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
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解题方法
2 . 已知
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/763d061631872c611d5662f7229127a6.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39b44ed068bce3a71927cf342fe06e8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/763d061631872c611d5662f7229127a6.png)
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解题方法
3 . 已知向量
,
,若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd707b69a11f8de5566f23c1a2a9ff5a.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43fa9307f35580493bf435ac6a464b25.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd5a6d96e46431eb0d20b531facda401.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b1fb8d0f0cd61691eebcea7cf67a950.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd707b69a11f8de5566f23c1a2a9ff5a.png)
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解题方法
4 .
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dab3fdf447d0736883fd4e74acd7f3e.png)
A.![]() | B.1 | C.![]() | D.![]() |
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解题方法
5 . 函数
是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7d532b8d4c5def4e646d8415839b6b4.png)
A.最小正周期为![]() | B.最小正周期为![]() |
C.最小正周期为![]() | D.最小正周期为![]() |
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解题方法
6 . 已知复数
是关于
的一元二次方程
(
,
)的一个根,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acaab42500ffbc4e1d36b55b76967421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f43e49552a5099a8b2a442247c65a243.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3276b5e12396fc4753eb3f8254f9fa68.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/934d37c81b2266c7b86bcc11afaf5f91.png)
A.![]() | B.![]() | C.19 | D.31 |
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7 .
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc2f5958898d19d54d893206be07485b.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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名校
8 . 已知变量y与x存在线性相关关系,根据一组样本数据
,用最小二乘法建立的线性回归方程为
,则下列结论正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d23a8ce02bc62a90c83ae361d580e094.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18e9372a046908377ea106c8f824b554.png)
A.变量y与x具有负的线性相关关系 |
B.若r表示y与x之间的样本相关系数,则![]() |
C.当变量![]() ![]() |
D.当变量![]() |
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9 . 小明研究函数
的图象与导函数,经查阅资料,发现
具有下面的性质:若函数
在
上的导函数为
,且
在
上也存在导函数,则称函数
在
上存在二阶导函数,简记为
.若在区间
上
,则称函数
在区间
上为“凹函数”.请你根据以上信息和所学知识,判断以下函数在其定义域上是“凹函数”的有( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/942c2141d01bde6b48210c56a17fc75e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4562f3225c98cf5cb11b47d98c9cc9c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/724340d69477c0ec2418c392b22b1cab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/724340d69477c0ec2418c392b22b1cab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4562f3225c98cf5cb11b47d98c9cc9c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/942c2141d01bde6b48210c56a17fc75e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4562f3225c98cf5cb11b47d98c9cc9c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/affdb4e0e91ead05b2684c52f341d935.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4562f3225c98cf5cb11b47d98c9cc9c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8df0dd6144e9a30d1a063b690033c3f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/942c2141d01bde6b48210c56a17fc75e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4562f3225c98cf5cb11b47d98c9cc9c3.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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