如图,在四棱锥
中,四边形
是直角梯形,且
,
,
,
,
,
是正三角形.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/10/7e81f0e2-56e6-417b-bf10-84914e1ac594.png?resizew=164)
(1)求证:
;
(2)求平面
与平面
所成角的余弦值.
![](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/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4bd6a2b112facda441f4e34bf5c145fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7ea9d92e5c258a50af1e461c7388894.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be41b05e11ba5eadaaed9a224b949774.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2205cffebf8c4d5f81d15ed7b85c8936.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/10/7e81f0e2-56e6-417b-bf10-84914e1ac594.png?resizew=164)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bafa8c14100a4f847b41b9148954116c.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
更新时间:2023-11-16 12:37:11
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】如图,三棱锥
中,
,
,
,平面
平面
分别为棱
的中点.
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/618aaecadee80a640c0019db0e9e2ae9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e0595498034037b58538f8056dbc6f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/baf42acb8d1875acf1775e30ae2e3d62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b12fa54e80fc52de0701cddc9a4ed47e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fbb19cb4eb2d7f3207559eb07355ba2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13259de331de43dda25f2688b7822663.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
解题方法
【推荐2】如图,在直四棱柱
中,
,
,
,点
为棱
的中点.
![](https://img.xkw.com/dksih/QBM/2017/4/7/1660717184548864/1661321455394816/STEM/26a1c49070824dd793d7bf41785e65b6.png?resizew=283)
(1)证明:
;
(2)若
为线段
上一点,且
,
为
的中点,求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd8e727e4efc22b49649f71ae9c9d84.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9060f03b9ee41d70d135b1e1a8902ce9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/991cc40b463d71e8f8667a7f23fba603.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f66fb71b75b63594ebeeeebd1963eed5.png)
![](https://img.xkw.com/dksih/QBM/2017/4/7/1660717184548864/1661321455394816/STEM/26a1c49070824dd793d7bf41785e65b6.png?resizew=283)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b937442ad4cc480adc11bb143559454.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f2a245381e615882ee5feb7793a1df6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73893c8f3960b2f84a67da3078d65a7a.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐1】如图,四棱锥
中,
,
,
,
,
为线段
上一点,
平面
,平面
平面
.
![](https://img.xkw.com/dksih/QBM/2022/2/9/2912826693599232/2937419880587264/STEM/1524f248-3962-43db-9935-99ca72bad3d5.png?resizew=185)
(1)求
;
(2)若三棱锥
体积为
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b44f35cd75d6f41841226872b76214cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b2fe247c83810ac43b3b6dfa749cad0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/714cc3707bba3bfdb56e251999be8592.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32d0710321d97361e5782124bbf7f0c9.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/f8c2b786c64e6a9ed2ec5670cde74f86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21e6dc2c16b657672402b9b189d1ad04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://img.xkw.com/dksih/QBM/2022/2/9/2912826693599232/2937419880587264/STEM/1524f248-3962-43db-9935-99ca72bad3d5.png?resizew=185)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/add47889f6b4911133999a898d3666d3.png)
(2)若三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1112ffa328ed486ffc5e4a605eb510e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf31876698721a199c7c53c6b320aa86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/324d453870b345da0c41977290192f94.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
解题方法
【推荐2】如图,四边形
与
均为菱形,
,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/1/5865decd-e504-4687-809e-197f7fba2f3f.png?resizew=200)
(1)求证:平面
平面
;
(2)求证:
平面
;
(3)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f84f169e50dc59d4f7a8e1e36f5c847.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6da20f949db06cbc10f052a7f8466019.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1f944d655ba3e2325d5a95a01e6ff85.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/1/5865decd-e504-4687-809e-197f7fba2f3f.png?resizew=200)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42ce82a4c37365f2d4dea2c4ad2e3288.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/111da2c687a67fd089c365090908eb00.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2194add18a7df1a23cf1554dc2da1b40.png)
(3)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed7a8116d2f02b52c33fb7a49fc0d1ae.png)
您最近一年使用:0次