1 . (1)在
中,若
,则
一定是__________ 三角形
请填写锐角,直角,或钝角![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04582116cd765fcc5a52f44279ad6c94.png)
(2)
中,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f774cd650f14c8f6e4fe0c6a432768bb.png)
_________ .
(3)已知复数z满足
,则
的最小值是________ .
(4)如图所示,空间四边形ABCD中,两条对边
,
分别是另外两条对边
上的点,且
,则异面直线AB和CD所成角的大小为___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30ee200d87dc576c5259be96bc0431c1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a301324443eb93b467134a86890dd9ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04582116cd765fcc5a52f44279ad6c94.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edc56eba6d1e1c9d293d648a756de4e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f774cd650f14c8f6e4fe0c6a432768bb.png)
(3)已知复数z满足
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/839ba7c0f1fc30151d18a2e337951dd2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf22958b9d397bce8d3b950c8fefbae8.png)
(4)如图所示,空间四边形ABCD中,两条对边
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/51e0f9d0d28bfb81ad132e0064402573.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d93949d8a15aca4e79cedb978590571.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65367e9651ecd42fce6a7ae585a5d4a3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/13/fb8817ed-8550-418d-a744-bf78d0539598.png?resizew=167)
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2 . 在下列命题中,正确的命题有________ (填写正确的序号)
①若
,则
的最小值是6;
②如果不等式
的解集是
,那么
恒成立;
③设x,
,且
,则
的最小值是
;
④对于任意
,
恒成立,则t的取值范围是
;
⑤“
”是“复数
(
)是纯虚数”的必要非充分条件;
⑥若
,
,
,则必有
;
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fde64f4d3c38e43fbdee24eadc4b0dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ef389807e5cb964f7756c6841f7161d.png)
②如果不等式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fae8fff7c98b78992edcd61daf6ea72f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef7b2668d8fcf713370822c8e368ba7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4da693578d4cd0c841fd529fe7ebfe4d.png)
③设x,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2519954ec2deabecd7e057886fa4023c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5558c083d34cbb0a58d3ce1dc6f5778e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa8887f77124cbe18a4931826ede9c9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b2a698891d42c70b597f0da4f215f09.png)
④对于任意
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b687f97094676b2755bc724219a58520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10ce220e0583c843810d4b44de111156.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f49bc53d70ee599df5cad39f06f728c2.png)
⑤“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f22a4a0dd7307a1323d25331e60782d8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21d96d22950baabd8ca6647205f1d3cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1e69392d21261afd8e5e5f096634669.png)
⑥若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae2e606c883dace7fbd88223c8067885.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a9d3040a7a1fc2cf8ac555dbafc97dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc277eef249facf647e13a58e3c2fe26.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/297a7062ba8f240d7517f0dd3ee6a27d.png)
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