已知直角梯形
,如图(1)所示,
,
,
,
,连接
,将
沿
折起,使得平面
平面
,得到几何体
,如图(2)所示.
(1)求证:
平面
;
(2)若
,求二面角
的大小.
![](https://img.xkw.com/dksih/QBM/2018/2/10/1879305908609024/1880540659589120/STEM/efdd66d17d754587a503623ffd824513.png?resizew=187)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49149989ccd8350bf530c7cb750f7014.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f121eabff3c62c1a196d9ca5f6f83f0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e673ef2d48215ca84a48377f17d6df00.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3d7090639341730951c1bc3c9b6164e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c41ffdaecfb3c73d403179e5745c71a8.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca5dd496ee0c1170ef6dcc48266ee444.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/490796b9624a00d9357a4b808b017ebc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42f4096ff62b4f29932cd8c6eef661a3.png)
![](https://img.xkw.com/dksih/QBM/2018/2/10/1879305908609024/1880540659589120/STEM/efdd66d17d754587a503623ffd824513.png?resizew=187)
![](https://img.xkw.com/dksih/QBM/2018/2/10/1879305908609024/1880540659589120/STEM/6ceac1f969c041a2a33c00312b1ec30f.png?resizew=197)
更新时间:2018-02-12 07:52:40
|
相似题推荐
解答题-证明题
|
适中
(0.65)
名校
解题方法
【推荐1】如图,四面体
中,
分别是
的中点,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/31/5dbe37b3-8243-4262-8c1f-c6d5e5ca529a.png?resizew=171)
(1)求证:
平面
;
(2)求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62e7f10e0c8af2d0d02a685f6f19e329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5016f2cf1328d15d090597514b63045.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a65d5853c26657db448af610ac72cca4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6559aabe16c2318687089e7cc498b98.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/31/5dbe37b3-8243-4262-8c1f-c6d5e5ca529a.png?resizew=171)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ce03b310edce42191f9fa75a1c909ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ade68d3f913ba0357f38a808392f5820.png)
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【推荐2】如图,在四棱锥P-ABCD中,底面ABCD为正方形,∠PAB=90°,PB=PD,PA=AB,E为线段PB的中点,F为线段BC上的动点.
![](https://img.xkw.com/dksih/QBM/2021/7/10/2761329134641152/2777295893512192/STEM/e1bc1fe919ec416bbcc5be177ab4ebcb.png?resizew=199)
(1)求证:AE⊥平面PBC;
(2)是否存在点F,使平面AEF与平面PCD所成的锐二面角为30°?若存在,试确定点F的位置;若不存在,请说明理由.
![](https://img.xkw.com/dksih/QBM/2021/7/10/2761329134641152/2777295893512192/STEM/e1bc1fe919ec416bbcc5be177ab4ebcb.png?resizew=199)
(1)求证:AE⊥平面PBC;
(2)是否存在点F,使平面AEF与平面PCD所成的锐二面角为30°?若存在,试确定点F的位置;若不存在,请说明理由.
您最近一年使用:0次
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【推荐3】如图,在四棱锥
,底面
为平行四边形,
为等边三角形,平面
平面
,
.
(1)设
分别为
的中点,求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42887d9bf31c1dd99f13c39e63c9ab9.png)
平面
;
(2)求证:
平面
.
![](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/177678001b2ccde1db8f57fa5e017002.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d077f6da8b2c00b152d4679aa2ed7f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b44f4120c94cb7176dc31fcac387b32e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/12/cc2762dd-0136-4d75-88be-a47f2bd49888.png?resizew=186)
(1)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0f3ed5ea1cf0fa8f7c6be46cd5fa057.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fc9553d0fa450786b888561368b7194.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42887d9bf31c1dd99f13c39e63c9ab9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/638537c0a30676c73fea76c80e0f8bd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
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【推荐1】如图1所示,
为矩形,四边形
为正方形.
与
为全等的等腰梯形,其中
,沿着
,
,
,
折成如图2所示的几何体
,使
,
,
,
分别与
,
,
,
重合.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/26/746ab1fa-0fe3-4683-b40b-5c265ad3e8e2.png?resizew=435)
(1)求证:平面
平面
;
(2)求平面
与平面
所成的锐二面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9836949f7896f7b329ec653225a4c765.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e9c5b620817b589ed8a26aeefb2f313.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67d822262ff00915910e5b87d81ad1ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97c01fdc7bc471af0b264a04aef0823e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6795cae2df43a722e1355e9562d93c09.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/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/26/746ab1fa-0fe3-4683-b40b-5c265ad3e8e2.png?resizew=435)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a45953045e613b97eeee15ac188ae2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b0a582c36d62d83c16425b2f54b4354.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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解答题-问答题
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解题方法
【推荐2】如图,一张平行四边形的硬纸片
中,
,
.沿它的对角线
把△
折起,使点
到达平面
外点
的位置.
(Ⅰ)△
折起的过程中,判断平面
与平面
的位置关系,并给出证明;
(Ⅱ)当△
为等腰三角形,求此时二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c2a839b1439349843a217a37e65d9ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dea4f5da4057387fc2ccaebc3de99fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21ea52361458ce2e49ed0fe99d8e6c02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44ffbe62bae95501e6b8e1ed2cadea57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9a7e0e5238148676a584b1748e04d3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c2a839b1439349843a217a37e65d9ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(Ⅰ)△
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44ffbe62bae95501e6b8e1ed2cadea57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c2a839b1439349843a217a37e65d9ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/197981dd0da1e48ef7cca6690a50b378.png)
(Ⅱ)当△
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f1854ba6cc92481d7a616bd2788a47e.png)
![](https://img.xkw.com/dksih/QBM/2012/2/27/1570778857463808/1570778863173632/STEM/463c6dceada24bb48bdc493d4d27eff5.png?resizew=245)
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【推荐3】如图,在四棱锥
中,底面
为平行四边形,
,
平面
,
.
![](https://img.xkw.com/dksih/QBM/2021/9/14/2808027926511616/2808870266445824/STEM/651a2655-97e0-4a24-9f2f-fdaf1f5d8850.png?resizew=268)
(1)证明:
平面
;
(2)若
,PB与平面
所成角的正弦值为
,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/3c4cb73e9d976cbfe9c590044fa69dd5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e5ea309886e947ea7cb4b81716206fd.png)
![](https://img.xkw.com/dksih/QBM/2021/9/14/2808027926511616/2808870266445824/STEM/651a2655-97e0-4a24-9f2f-fdaf1f5d8850.png?resizew=268)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ffc6952e988d04f22f0fb2f7f0ab7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f571a1aac46c6d0cf440c0ec2846bf9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21ea52361458ce2e49ed0fe99d8e6c02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83c7a937699f989b685f285041434000.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dee14db57f0c762aad845cf5b4a243c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1069d514c3c32aeabd274475ee209ed6.png)
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