1 . 如图,在直三棱柱
中,
,
,点
分别为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/2/47a8cfee-5b21-48c1-aa55-334f8e134438.png?resizew=181)
(1)证明:
平面
;
(2)若
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83beb9fd65e75633d2d5e7b010693899.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c3e9ef3e849788645552cfb0735d987.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38946e8e92738baf91f63f937af3d8bd.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/2/47a8cfee-5b21-48c1-aa55-334f8e134438.png?resizew=181)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edcf19a7f0dd0cdf59516ae585025110.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc6184b191e6da43911e701121517e.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84bd173466089f8e523dc02808239daf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2da84a0e9aac2c68de71c26f2ea4761.png)
您最近一年使用:0次
2017-10-26更新
|
993次组卷
|
2卷引用:2020届广西梧州市蒙山县蒙山中学高三上学期第一次测试理科数学
2 . 如图甲,设正方形
的边长为3,点
、
分别在
、
上,且满足
,
.如图乙,将直角梯形
沿
折到
的位置,使得点
在平面
上的射影
恰好在
上.
![](https://img.xkw.com/dksih/QBM/2018/8/30/2021615741288448/2039873270702080/STEM/7c61b5a25eb44385b5b89bf470301308.png?resizew=284)
(1)证明:
平面
;
(2)求平面
与平面
所成二面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.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/a02c25b95e61557eec096de150ab873f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87ef0a99a25b115e054452abff205544.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/946c16d99496d31ce4d87301a4793393.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01ea0cd736da605b021de1a0daaeffee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ab7434c183e59a4efdec91a1a8bdf50.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a6480f384476190883f06c0289c7519.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/2018/8/30/2021615741288448/2039873270702080/STEM/7c61b5a25eb44385b5b89bf470301308.png?resizew=284)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaff0124162c576baab5919e6c7a6beb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbcfe92b25904211a9d1ebc69f07f196.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a6480f384476190883f06c0289c7519.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01ea0cd736da605b021de1a0daaeffee.png)
您最近一年使用:0次
2016-12-02更新
|
672次组卷
|
3卷引用:2020届广西梧州市蒙山县蒙山中学度高三上学期第二次测试理科数学试题
3 . 如图,已知四棱锥
中,底面
为菱形,且
,
是边长为
的正三角形,且平面
平面
,已知点
是
的中点.
![](https://img.xkw.com/dksih/QBM/2016/11/25/1573180774187008/1573180780601344/STEM/2bee746e-3f3a-40b2-a740-b11cbdc2a04a.png?resizew=241)
(1)证明:
平面
;
(2)求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48b7f92d9ab08250f5050e0b8122aea1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/703b40a6293ed9e33001e2919379b168.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://img.xkw.com/dksih/QBM/2016/11/25/1573180774187008/1573180780601344/STEM/2bee746e-3f3a-40b2-a740-b11cbdc2a04a.png?resizew=241)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30067b7b236d17af8a462f96a58d11bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53bdef2e7a7929ad6190302ab44c46c0.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53bdef2e7a7929ad6190302ab44c46c0.png)
您最近一年使用:0次
2016-12-05更新
|
1049次组卷
|
3卷引用:2017届广西梧州高三上摸底联考理数试卷
4 . 如图,DA⊥平面ABC,DA∥PC,∠ACB=90°,AC=AD=BC=1,PC=2,E为PB的中点.
![](https://img.xkw.com/dksih/QBM/2015/3/27/1572039932092416/1572039937966080/STEM/49fcc111cbd641afa4151c6dc620b7c5.png?resizew=136)
(1)求证:DE∥平面ABC;
(2)求二面角E﹣CD﹣B的余弦值.
![](https://img.xkw.com/dksih/QBM/2015/3/27/1572039932092416/1572039937966080/STEM/49fcc111cbd641afa4151c6dc620b7c5.png?resizew=136)
(1)求证:DE∥平面ABC;
(2)求二面角E﹣CD﹣B的余弦值.
您最近一年使用:0次