如图,三棱台
,平面
平面
,侧面
是等腰梯形,
,
分别是
的中点.
![](https://img.xkw.com/dksih/QBM/2022/1/25/2902016318652416/2902719550996480/STEM/8744cd04-a4ba-4d61-8149-46f06f6398d9.png?resizew=175)
(1)求证:
平面
;
(2)求
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73a9ad711b25c36dae0c2a2cedff9954.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df00cdf77ed39ca5a0b305861a693142.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e53b212640dadf751ef7f65a78a209.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bc3216d0caeb19d4d867c9a890b86a6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dd7e73c6c794d005c36f08e38283639.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22242f6fbf434d9d4a2012f8a4087857.png)
![](https://img.xkw.com/dksih/QBM/2022/1/25/2902016318652416/2902719550996480/STEM/8744cd04-a4ba-4d61-8149-46f06f6398d9.png?resizew=175)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afabf56cc68ea438a890f9fea04b708e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88e6e9dbc333577a1ac8d31f1597ace4.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19ef601ca1f9c4c031adab4ffed297f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a211ad5a06b505b8365a62c1946f3cb7.png)
更新时间:2022-01-26 12:20:57
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相似题推荐
解答题-证明题
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【推荐1】如图,在直三棱柱
中,
,
,
分别是
,
,
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/6/7aa2365f-f45d-47d0-a510-22b2eeff3b12.png?resizew=146)
(1)求证:
平面
;
(2)若
,求证:平面
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.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/56f7ba05c54b3de1f4378f7c8eb58328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/6/7aa2365f-f45d-47d0-a510-22b2eeff3b12.png?resizew=146)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f16835e3f230ba3f543b6804e445e283.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7935fe3125f247b7bea4f065ce9ad985.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f9b0421e0b4d74b22df706578b74a58.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba0fbd88fdb064072eedd136e9cb41ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc6184b191e6da43911e701121517e.png)
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解题方法
【推荐2】正三棱柱
中,
,
,点
分别为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/10/672a192a-baae-4541-b424-bcabcc359cf7.png?resizew=230)
(1)求证:
面
;
(2)求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ced06b71073e1bb777f326f06016ce17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41fd676c41d2d644928f014b0fea4689.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91e1e4115d78e625e9e0f47cdade3286.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c1200f6b6773bbe445ccfd4cb6f68f3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/10/672a192a-baae-4541-b424-bcabcc359cf7.png?resizew=230)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b78172568aac9805d2ea2d5f742bf80c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5445220e9b81a876e359615859a5a58.png)
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【推荐3】如图,四棱锥
的底面
是直角梯形,
,
.
底面
,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3bd9897b70dd486e20442590da96ce5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/85d7a531-c70c-4a32-86a9-4b4e5d938d3c.png?resizew=187)
(1)证明:
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/1134c8e3440abb6cd385af2c169037fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec895213ee462736ea4da8f28b89d02b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3bd9897b70dd486e20442590da96ce5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/85d7a531-c70c-4a32-86a9-4b4e5d938d3c.png?resizew=187)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/932a04304f2d4975955d4baabb2deeea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1069d514c3c32aeabd274475ee209ed6.png)
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【推荐1】已知A是△BCD所在平面外的点,∠BAC=∠CAD=∠DAB=60°,AB=3,AC=AD=2.
(1)求证:AB⊥CD; (2)求AB与平面BCD所成角的余弦值.
(1)求证:AB⊥CD; (2)求AB与平面BCD所成角的余弦值.
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【推荐2】如图,在四棱锥P-ABCD中,
底面ABCD,
,
,
,
,E是PC的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/16/2bda7570-8541-47b1-beef-792cbd959ec8.png?resizew=154)
(1)求PB和平面PAD所成的角的大小;
(2)证明
平面PCD;
(3)求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1134c8e3440abb6cd385af2c169037fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3bf10d92f20501e19d25f6f4159aab89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ace900749d0861aa51fcc6d72c51f82c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/16/2bda7570-8541-47b1-beef-792cbd959ec8.png?resizew=154)
(1)求PB和平面PAD所成的角的大小;
(2)证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f4c3f9dd5d0343597a7f58a1989b537.png)
(3)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e867e5c7ef4da37d8985ce82022060e.png)
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【推荐3】已知P为所在平面外一点.
(1)若O为P在平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a15a004f7d47ed595f063e60075223a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccbd1316b9d1f0c1e71fd078deec61f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30fc65a72853bd8ac1ad0828270d3baf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
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