如图,在四棱锥
中,
平面ABCD,底面ABCD是菱形,
,
.
![](https://img.xkw.com/dksih/QBM/2020/2/22/2410915108888576/2412276975927296/STEM/a71101c7-8cc2-4285-9f31-48b5e8c9e479.png)
(1)求证:
平面PAC;
(2)若
,求二面角
的平面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f945a69cf7e8213e50622125cde652f5.png)
![](https://img.xkw.com/dksih/QBM/2020/2/22/2410915108888576/2412276975927296/STEM/a71101c7-8cc2-4285-9f31-48b5e8c9e479.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a5928c98b341b16d4b5a5b931d2929d.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/829f9180ddd9aa1a0ee0dc520f4e0b5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a438393ddfc7da1804baf4932442bb35.png)
更新时间:2020-03-04 14:12:58
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】如图,在多面体
中,四边形
为矩形,
,
,
,
,
,
,
,
是
的中点,
为
上一点(
不是
的中点).
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/3/52c51480-5d7e-441a-9763-84069e146373.png?resizew=159)
(1)求证:
;
(2)若
,求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27e5016c9137ae6cac7d5b83cea41771.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0d5a2cd05e4476fc72271e8fdb59a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36d3f9afa268a42005c3dcfa681b2865.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f900d8744217015f808d935656c2857b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d35422eefe3bd40cb553e7a6b30c1be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3aab042d07ad294994e7d250cffba9f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ff30e155c09e316411d9b5eaabad815.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcdae78f4d3b8d8213ac3ac9a9567eb5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/3/52c51480-5d7e-441a-9763-84069e146373.png?resizew=159)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6f86d9ca130443b8effd507f50364c6.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adfbbd8c8a5727b631af2a43ab06a677.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70db40c42655327adee01caedfc9d50c.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
解题方法
【推荐2】如图,平面五边形
中,∠B=∠BAD=∠E=∠CDE=90°,
,将
沿
折叠,得四棱锥
.
![](https://img.xkw.com/dksih/QBM/2022/5/17/2981525741993984/2981984559243264/STEM/0a03581c-80cb-4bd2-90b7-4a59b0b1191d.png?resizew=288)
(1)证明:
;
(2)若平面
平面
,求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34da6e9e781efa09d4fb30db42ec6de1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27c9a77f3dcaacefe3ee0a64ddf7f73a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://img.xkw.com/dksih/QBM/2022/5/17/2981525741993984/2981984559243264/STEM/0a03581c-80cb-4bd2-90b7-4a59b0b1191d.png?resizew=288)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/352d85caf2bd9c6c66709d09df0ee0ac.png)
(2)若平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
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解答题-问答题
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适中
(0.65)
名校
解题方法
【推荐1】已知四棱锥
中,底面
是矩形,
,
.
平面
;
(2)求二面角
的余弦值.
![](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/c2b51401875599d32a2ec41b70ac75e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cae4011a59f40f68793bb41a7982b93c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d077f6da8b2c00b152d4679aa2ed7f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78d07f36efcb9d203267d7c0409720cf.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐2】如图,直角三角形
中,
,
,
,
为线段
上一点,且
,沿
边上的中线
将
折起到
的位置.
(1)求证:
;
(2)当平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f571a1aac46c6d0cf440c0ec2846bf9.png)
平面
时,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5b8b98b2f83279a49e94d9f48c5e6f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45acdbac251ca6b76a166c1242e71df9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa12e62b31e4d483e097598aef8bafe6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acee03d4bb4667b6c345221b6c9b0fa4.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d31767eb718a0327eca546fe6a189cb.png)
(2)当平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f571a1aac46c6d0cf440c0ec2846bf9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56ad3801636f311f226766d93859851e.png)
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