1 . 如图,在三棱锥P—ABC中,PC⊥底面ABC,AB⊥BC,D,E分别是AB,PB的中点.
![](https://img.xkw.com/dksih/QBM/2015/10/26/1572264677883904/1572264683847680/STEM/69c6e4fe-e139-4edb-a9b0-194f2e345fc9.png?resizew=245)
(Ⅰ)求证:DE∥平面PAC.
(Ⅱ)求证:AB⊥PB;
(Ⅲ)若PC=BC,求二面角P—AB—C的大小.
![](https://img.xkw.com/dksih/QBM/2015/10/26/1572264677883904/1572264683847680/STEM/69c6e4fe-e139-4edb-a9b0-194f2e345fc9.png?resizew=245)
(Ⅰ)求证:DE∥平面PAC.
(Ⅱ)求证:AB⊥PB;
(Ⅲ)若PC=BC,求二面角P—AB—C的大小.
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2016-12-03更新
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4卷引用:宁夏银川市第九中学2019-2020学年高一上学期期末数学试题
2 . 如图甲,直角梯形
中,
,
,点
、
分别在
,
上,且
,
,
,
,现将梯形
沿
折起,使平面
与平面
垂直(如图乙).
(Ⅰ)求证:
平面
;
(Ⅱ)当
的长为何值时,
二面角
的大小为
?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f79863ffcfa63117ca6741b20a48e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2324805c5dfe2a35787bc3af840586ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f479d987bc7abd828c64f9dc745836ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c54b729996e63624d896ac0409083c28.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef0402dd5ae3db10281f9f1e11738bcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d8511eeface9029eeaeaf60ec2c722d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b80a0e428cb894bfd09a6129a73ea4ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9238757804254960bc40fa9d87065559.png)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/307807ee10071bafbe922eb18d2517d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2f2ff8aae606dbc83ed086be4405c75.png)
(Ⅱ)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3533837e3d08c461dea031a44e5424d.png)
二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/894a171f4b92c437544ba372348f41c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/996bf3d35b6763cbc1a423b13a9df2dd.png)
![](https://img.xkw.com/dksih/QBM/2016/4/7/1572568923701248/1572568930066432/STEM/fec3ca1f-1550-4031-90ad-dc2c688ac597.png?resizew=427)
您最近一年使用:0次
2016-12-04更新
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570次组卷
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7卷引用:宁夏银川一中2020-2021学年高二上学期期末考试数学(理)试题
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