如图,在四棱锥
中,
底面
,底面
为直角梯形,
分别为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/29/8d055392-d48a-44f6-a7f2-ff848b2b576f.png?resizew=175)
(1)求证:
平面
;
(2)若截面
与底面
所成锐二面角为
,求
的长度.
![](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/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbc1bead464651e111b3b6a886859e79.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a211a44ffb09c7413dac58e9cea70fd9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/29/8d055392-d48a-44f6-a7f2-ff848b2b576f.png?resizew=175)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94270844f197d524bf1da4f1385befd2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)若截面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6261790c66cc71ee3898afabad0c09f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af9955b5aebb73cd84447e8541f901ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
更新时间:2020-07-05 16:51:07
|
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解答题-证明题
|
适中
(0.65)
名校
解题方法
【推荐1】如图所示,在四棱锥
中,BC∥平面
,
,E是
的中点.求证:
∥平面
;
(2)
∥平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e306e30d3159e4a68435c3fcfc8da693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
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解答题-问答题
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适中
(0.65)
解题方法
【推荐2】如图,在四棱锥
中,底面
为直角梯形,
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0bfa7955ba2d721172673682281df42.png)
,
,平面
平面
,
为
的中点.
![](https://img.xkw.com/dksih/QBM/2022/5/9/2975774629707776/2976656776462336/STEM/60b2be64381d453e86a9ba03adf17fe3.png?resizew=258)
(1)证明:
平面
;
(2)求多面体
的体积.
![](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/d39681bd16fa20a6616da67aab6d95ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0bfa7955ba2d721172673682281df42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0204f76cda5ea4ced714588be1efeaa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa7aeb2a8d1437eeb4482c3b6ad9f315.png)
![](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/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://img.xkw.com/dksih/QBM/2022/5/9/2975774629707776/2976656776462336/STEM/60b2be64381d453e86a9ba03adf17fe3.png?resizew=258)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa14afe6f0aad22e8e869c39a60be657.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
(2)求多面体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64198065b66a9a3491f8e48fc8b9d2ee.png)
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解答题-证明题
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解题方法
【推荐1】如图,在三棱锥
中,平面
平面BCD,
,O为BD的中点.
(1)证明:
.
(2)若
是等腰直角三角形,
,
,点E在棱AD上(与A,D不重合),若二面角
的大小为
,求点D到面BCE的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcf6dc837ae85207789b94d109c5c2eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74a96505772b351417a4c832c407c987.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/1/095f06bd-55a3-4619-9bab-00fa229a8ac9.png?resizew=177)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21be01a95cdd3149512bf95d6084fdd6.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/661ff55b5ebbadfb600989af3cfce2fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1347b1707478d309af4287a00e852b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/833cfda415649b832cc136caed392753.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/324d453870b345da0c41977290192f94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1e5fa72f2878b476bc57f0df12d6555.png)
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【推荐2】如图,四棱锥
中,底面
为矩形,
平面
,
为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/6/0e7cb762-7324-48cb-adc9-94501483c4b7.png?resizew=198)
(1)证明:
//平面
;
(2)设
,
,若二面角
的余弦值为
,求
的长.
![](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/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/6/0e7cb762-7324-48cb-adc9-94501483c4b7.png?resizew=198)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46e2da608b66c9aee03e2503388ba4fd.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d783fe7f3ce673d5d21281174e7a7968.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a03a08e6ea74ee085ed9dd4a05af94c2.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
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【推荐3】如图所示,在四棱锥P—ABCD中,
,
,
,
,E是边AD的中点,异面直线PA与CD所成角为
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/8/14dba2d4-0559-45be-92e9-9796f648de07.png?resizew=175)
(1)在平面PAB内找一点M,使得直线
平面PBE,并说明理由;
(2)若二面角P—CD—A的大小为
,求直线PA与平面PCE所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4adf90a8c2b29334cdc5aa5b554991f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a0e5697eca3f5205cb7b343648240bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cbb05b8b630052ff544249ebd72d95d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3384e2b63e4be03a8762b819499e669b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1ad72d7565699d1ebb741eb0ce12bac.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/8/14dba2d4-0559-45be-92e9-9796f648de07.png?resizew=175)
(1)在平面PAB内找一点M,使得直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa14afe6f0aad22e8e869c39a60be657.png)
(2)若二面角P—CD—A的大小为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c67d01e61dc0042e67b5e8ec8e727c22.png)
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