如图所示,在
中,斜边
,
,将
沿直线AC旋转得到
,设二面角
的大小为
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/26/f175090b-a36a-484f-b450-19cc80ab7896.png?resizew=195)
(1)取AB的中点E,过点E的平面与AC,AD分别交于点F,G,当平面
平面BDC时,求FG的长;
(2)当
时,求二面角
的余弦值.
(3)是否存在
,使得
?若存在,求出
的值;若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8a7b5adfcac0f46a4cd19da4ebb4a2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26fdd8e57562ba94e10e7f1d770826d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7ac5396c5ea442e0364b50c1db3d2da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f0ac3005d5ecd6d4cea0ce99a47ef3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05df5a26c2b978503e93efa040b99508.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/26/f175090b-a36a-484f-b450-19cc80ab7896.png?resizew=195)
(1)取AB的中点E,过点E的平面与AC,AD分别交于点F,G,当平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1fd975b889bfe7ddcec0de56b6f23ee.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33ac762a2899a58faa0d3ab44f1281fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f4b5d1c31f399d19286c4b82abb790.png)
(3)是否存在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d045abc40b9acb8d6d1f4d80cb4655e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
更新时间:2021-10-16 07:51:06
|
相似题推荐
解答题-问答题
|
较难
(0.4)
【推荐1】如图,在四棱台
中,
∥
侧面
,
为
的中点,
为棱
上的点,
∥平面
.
∥平面
;
(2)求
;
(3)求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ef7c9d8be40b29e3459d97cc56d1ae6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a926f9c523803bca48c5badcaa542561.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e873213d690523c78951f057798fb0ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.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/456175ea34492f0bc025aaab668fa659.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ebb05874eb3353d754af24c9974273e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bff3ccea5989c60e51e321af3f53f54.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ebb05874eb3353d754af24c9974273e.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
(3)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32bbdf5dbf9df96742624ada95c36146.png)
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解题方法
【推荐2】夹在两个平行平面间的两线段AB,CD或它们的延长线相交于点S,已知
,
,
,求线段CS的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1b96b6aa11c60dc9d174b9afdbb0392.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a2c28bf73bcef2b9bbc0de14c7fcfd7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/552b53b1bc1443be9198552724d9215b.png)
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【推荐1】如图,由直三棱柱
和四棱锥
构成的几何体中,
,平面
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a8181f7a7fe7f3fac872ce9534f15.png)
(I)求证:
;
(II)若M为
中点,求证:
平面
;
(III)在线段BC上(含端点)是否存在点P,使直线DP与平面
所成的角为
?若存在,求
得值,若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06b3e8bee41beb61f3c4afdc554cb455.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba90c0290ae59b9e4f150a48eed8de4c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98cf9cb5b6b6de8dd40dce5628d77a1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a8181f7a7fe7f3fac872ce9534f15.png)
(I)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a773326771e4d98979061f9949ee0af0.png)
(II)若M为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2eb89294b31ffdd2680b4361e8994d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ac480d8d9d7821b62a603cf5cfda236.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1477ae90a240deba97f8dadf4d7c41aa.png)
(III)在线段BC上(含端点)是否存在点P,使直线DP与平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1477ae90a240deba97f8dadf4d7c41aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d88591679796c52024d11c4de641bdb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4fb46419d4c5868342f6615adcd36d9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/4/5/f028d440-a7d1-4f85-8e59-f48b2e94ba81.png?resizew=148)
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【推荐2】如图,在四面体
中,
平面
,
.
,
.M是
的中点,P是
的中点,点Q在线段
上,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/7850d128-eb0e-4c88-bd91-0fe8f8c55fce.png?resizew=190)
(1)证明:
;
(2)若二面角
的大小为60°,求
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca5dd496ee0c1170ef6dcc48266ee444.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bd6a2b112facda441f4e34bf5c145fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d27bd71d79cb19eb554175e4ef0867.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e46571701ccaa18d3c844ab99ee6c30e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/276e3c9755dbd39fb01de614840d230f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/7850d128-eb0e-4c88-bd91-0fe8f8c55fce.png?resizew=190)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be742533a98206940a01156e5cd9ae30.png)
(2)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b70049601f57c8a2ece170c0a9c3c05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a72dfbf0138a611174c36ce077e0c47.png)
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名校
【推荐3】如图,在四棱锥
中,底面
是正方形,侧面
底面
,
,
分别为
中点,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/26/d501d3cb-322e-4c1f-9add-5a4e116a7a08.png?resizew=261)
(1)求证:
平面
;
(2)求二面角
的余弦值;
(3)在棱
上是否存在一点
,使
平面
?若存在,指出点
的位置;若不存在,说明理由.
![](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/93edc7bb513f40a89173121c8570cd65.png)
![](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/06e87d4d9a3b0f961483bf4f68be9c9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/931bbffda5e872703c9947eccc47ede2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/26/d501d3cb-322e-4c1f-9add-5a4e116a7a08.png?resizew=261)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38675b96e9409217b9e8ec34b80fff35.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8af558cc6819fc74127be2933360fd40.png)
(3)在棱
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36148e5b0d89ba45bd98b91da00bf2b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14af6bf74442941c372bb708bcdcb5e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
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解题方法
【推荐1】如图,在四棱锥
中,四边形
是边长为
的菱形,
,
,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/19/f78c27f9-3b5e-4a8e-9e40-916a8d467cfe.png?resizew=167)
(1)证明:平面
平面
;
(2)当四棱锥
的体积最大时,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faeb97acf19bd3b2c6c77c2814df4d2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05740f0c6071846227dc0ec177ad15e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/186c23c64ea26f2f72a72ef27ead8122.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/672ec1169bab663781450d42f39ffe6f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/19/f78c27f9-3b5e-4a8e-9e40-916a8d467cfe.png?resizew=167)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/877582b5387278008d14fe5932622fe7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)当四棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faeb97acf19bd3b2c6c77c2814df4d2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c53f1e79257ff52a0408fdc482488d0.png)
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真题
解题方法
【推荐2】右图是一个直三棱柱(以A1B1C1为底面)被一平面所截得到的几何体,截面为ABC.已知A1B1=B1C1=l,∠AlBlC1=90°,
AAl=4,BBl=2,CCl=3.
(1)设点O是AB的中点,证明:OC∥平面A1B1C1;
(2)求二面角B—AC—A1的大小;
(3)求此几何体的体积.
AAl=4,BBl=2,CCl=3.
(1)设点O是AB的中点,证明:OC∥平面A1B1C1;
(2)求二面角B—AC—A1的大小;
(3)求此几何体的体积.
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