如图,在三棱锥
中,
,
,侧面
为等边三角形,侧棱
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/4/4b0dcdec-5b27-47e7-b635-1e47ed54b2df.png?resizew=168)
(1)求证:平面
平面
;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/209acf15985d1ea1ad86fc4a37e38c0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ced8225ff27c8e3e1897b8629312d5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/4/4b0dcdec-5b27-47e7-b635-1e47ed54b2df.png?resizew=168)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e820aec9c1a975242fe6d76408a9cde8.png)
更新时间:2017-12-14 16:43:39
|
相似题推荐
解答题-证明题
|
适中
(0.65)
名校
解题方法
【推荐1】在平行六面体
中,
,
,
.
![](https://img.xkw.com/dksih/QBM/2020/7/20/2510137376497664/2511139541377024/STEM/095acdd97f634c40af3f8055471257b6.png?resizew=189)
(1)求证:平面
平面
;
(2)求直线AC与平面
所成角的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f34e6236108a3ac6ec69fed992e9114.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6906f59d09ce31956d6f5ea2b23fc77.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57efa81a14012a64af9a1e1ecbdb2d80.png)
![](https://img.xkw.com/dksih/QBM/2020/7/20/2510137376497664/2511139541377024/STEM/095acdd97f634c40af3f8055471257b6.png?resizew=189)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21dee56b9f36ba8f76fe67b76383636b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9edc50f7febbc2d5d8dcdc23a3630a7.png)
(2)求直线AC与平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9afac7c616bbb14e1ed428a3c507c7dc.png)
您最近一年使用:0次
【推荐2】已知平行四边形
中
,
,平面
平面
,三角形
为等边三角形,
,
.
,
分别为线段
,
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/29/2a6fbc0d-8524-4baa-b380-7ab08c5f9464.png?resizew=271)
(1)求证:平面
平面
;
(2)求证:平面
平面
;
(3)求直线
与平面
所成角的正切值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5b8b98b2f83279a49e94d9f48c5e6f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f80f51c31583fea58fde645474d60b8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec43f7352b3a8c194b4c37485fb4ffd8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97a9b32570d553161be04d13954e92a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e41d3f7d55fcbaebc4e2450ac63a3dc5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4901a7eda97d6a307db76c4fb196ba3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/29/2a6fbc0d-8524-4baa-b380-7ab08c5f9464.png?resizew=271)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea0d020a24cd4b60f858f3ff09da3bdf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ae8768996ca9a0f2c5d9a19abbd54df.png)
(2)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15f3e3f310f6ec3f3a26498e7ee17a00.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(3)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/735056c174e8dd7906257a2a50a962a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ae8768996ca9a0f2c5d9a19abbd54df.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐1】在等腰梯形ABCD中,E、F分别是CD、AB的中点,CD=2,AB=4,AD=BC=
.沿EF将梯形AFED折起,使得∠AFB=60°,如图.
![](https://img.xkw.com/dksih/QBM/2018/11/19/2078946342125568/2079091270238208/STEM/16843908698d4b75af2f8424f552323b.png?resizew=318)
(1)若G为FB的中点,求证:AG⊥平面BCEF;
(2)求二面角C-AB-F的正切值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
![](https://img.xkw.com/dksih/QBM/2018/11/19/2078946342125568/2079091270238208/STEM/16843908698d4b75af2f8424f552323b.png?resizew=318)
(1)若G为FB的中点,求证:AG⊥平面BCEF;
(2)求二面角C-AB-F的正切值.
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1,在
中,
是
边的中点,现把
沿
折成如图2所示的三棱锥
,使得
.
(1)求证:平面
平面
;
(2)求平面
与平面
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9178fc8b5d65aa75fa9196294a0db7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0de086238dd316679ee02617d906f5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79dd200766db27fb90d6bd1992cf658.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd9aed224abad6c436c7c1b4f05e48dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcfaca9396f85c0137b534903321fcbe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/797b63230014b6706774fac07fbea3c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df69a2811637fb24ca7f202662e3b461.png)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43241f57934797192bb048ea989eaebb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fc8ef8adf01fcdff495bb992233d52a.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/787ac5e13622afab5e9f8603afe42356.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12f9da0507a3ba13bb9e51bbb503d98d.png)
![](https://img.xkw.com/dksih/QBM/2017/2/28/1633793148125184/1634620011372544/STEM/4efa001376ec4f3ab0737b8617cea1f6.png?resizew=299)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐3】如图,在四棱锥
中,底面
为矩形,平面
平面
为
中点,
与
交于点
的重心为
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/10/9b357987-9137-4b63-9ea6-04afe4af86aa.png?resizew=178)
(1)求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e55e398e8520d8a36fb5a625a085b8.png)
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
(2)若
,求二面角
的正弦值.
![](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/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbd6f10ececa5670a3cf2f6b3348d82a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/683c590673eece14fea3319c4fd5eb55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a369e96207ddf8e489751852abcd73f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/10/9b357987-9137-4b63-9ea6-04afe4af86aa.png?resizew=178)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e55e398e8520d8a36fb5a625a085b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dde36f2493881e4c8027a8aeb908b886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dba5bc0ae7fd9f2a903415cc83c286e5.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐1】已知四棱锥
的底面
是梯形,
,
,
,
,
在棱
上且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/f2155f89-54a1-44bc-a5c1-e164783f9a55.png?resizew=174)
(1)证明:
平面
;
(2)若
平面
,异面直线
与
所成角的余弦值为
,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/68d31600cba2d5256c7e78b6122d6755.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce0d7095ddd69d6ceaf1065b1bc2c79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27db558e8db4c957654c8e5cecd2d2dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40560ea08d6cd8c1d4d9661ee6faaa3b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b384315ba84cafb978ef3619c8162b5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/f2155f89-54a1-44bc-a5c1-e164783f9a55.png?resizew=174)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c372d059202ec388960b125d4a87dc84.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)若
![](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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9868f77d5ab5073b6145f1c6d272122e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d682fd0344452998187cb6d48de3dd1.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐2】如图,在三棱柱
中,
平面
,
,点
分别在棱
和棱
上,且
为棱
的中点
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/3181653e-bcc7-4011-b78a-7d0ca999c3d7.png?resizew=149)
(Ⅰ)求二面角
的正弦值;
(Ⅱ)求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a8bfe2553e852df73185d017c0a62fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ee0ba30311db4b7187d19d0cdbe3bb2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c122ca7141c43c15c783968f5f0dbc19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91e1e4115d78e625e9e0f47cdade3286.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d8379e02133be85a72747674b14f86f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/3181653e-bcc7-4011-b78a-7d0ca999c3d7.png?resizew=149)
(Ⅰ)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4feab537a7aaa3ea5a47bbed9e9421c4.png)
(Ⅱ)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa279d85f7cb724fc05fe2917b3b8f8c.png)
您最近一年使用:0次