如图,在正方形
中,点
为
上动点,点
为
上动点,满足
,将
、
分别沿
、
折起,使
、
两点重合于点
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/5/9700c52b-1c2c-4787-8826-871aee194fe4.png?resizew=315)
(1)证明:
;
(2)若
,求二面角
的平面角的余弦值.
![](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/03902478df1a55bc99703210bccab910.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/d38d97f03faed3152db2fd3bd1919944.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2689f0ce5ab3467d8214794d8acb2bd6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8eff00441c41fc516c37876d266fcbc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/5/9700c52b-1c2c-4787-8826-871aee194fe4.png?resizew=315)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cfa8355d95bb4c8d7c004eab4c7ce784.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1cca2d187a304eab931eedc2139c23ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29f8c417f5c19cc076dc6baeb0c173a9.png)
更新时间:2024-01-05 09:28:46
|
相似题推荐
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】在梯形
中,
,
,
,
,如图1.现将
沿对角线
折成直二面角
,如图2,点
在线段
上.
;
(2)若点
到直线
的距离为
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a11029ca6b4b9e7f777af0280cf163c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8cfd06965af6014208127f2880b476b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080ca48cd27d4bf9d9ef084b558fc17a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9ac7094262811e033da37dd18ed8b12.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7ac5396c5ea442e0364b50c1db3d2da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf29d07c3751c41ab3503065a5a5052e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cdba1337ec85fa9722cb4b320a82ae6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b925e994247985e948757354d63ace2.png)
(2)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9868f77d5ab5073b6145f1c6d272122e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8180b12d96caf2e6b3ca28a474185e41.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
解题方法
【推荐2】如图,四棱锥
中,底面
是菱形,
,
是棱
上的点,
是
中点,且
底面
,
.
![](https://img.xkw.com/dksih/QBM/2021/3/24/2685023887179776/2686863790825472/STEM/e20e8e3c84534eef896de1d0e2a38274.png?resizew=302)
(1)求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ffc6952e988d04f22f0fb2f7f0ab7b.png)
;
(2)若
,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/7bb8fb552b9e21dbaba74d11aa747790.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3e126c16032892966489053f44b9048.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91991ef52812b1c9cecb28d865a06f54.png)
![](https://img.xkw.com/dksih/QBM/2021/3/24/2685023887179776/2686863790825472/STEM/e20e8e3c84534eef896de1d0e2a38274.png?resizew=302)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ffc6952e988d04f22f0fb2f7f0ab7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaf3369e0ea90e8d5cf4b6b3c45c0fd8.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63694e23772a3d3df7e23a0b0e88c27f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b04613266ef63f71bb8b2cc3b497803f.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,四棱柱
的底面
为矩形,
,M为
中点,平面
平面
,且
.
![](https://img.xkw.com/dksih/QBM/2021/12/5/2866007604772864/2867449097347072/STEM/7c0eb192-5a95-4975-b1ec-d4db9c7df9f0.png?resizew=249)
(1)证明:
.
(2)若此四棱柱的体积为2,求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b929269c53a44907dba8ee298a0a522.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41884a12fb840aff6012fe78e5ac2fb5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60e22c6b010410967789641c522fc1a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c3232a80d0d71fe3f3f0af470b1aa1a.png)
![](https://img.xkw.com/dksih/QBM/2021/12/5/2866007604772864/2867449097347072/STEM/7c0eb192-5a95-4975-b1ec-d4db9c7df9f0.png?resizew=249)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/796b217753ddf3e7616b534b624fea27.png)
(2)若此四棱柱的体积为2,求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff420795b334c9934c366b99507d0026.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐2】如图,在棱长为1的正方体
中,动点
在线段
上运动,且有
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/3/d0f16fb9-70f2-4e91-b11e-c3d85bca5fa7.png?resizew=157)
(1)若
,求证:
;
(2)若二面角
的平面角的余弦值为
,求实数
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab653c13b545c4b3541890b1d39e2d1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7785afeeaf274892253d04b4f693b367.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b601f966ee94feba49d5df17a5d1e92c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/3/d0f16fb9-70f2-4e91-b11e-c3d85bca5fa7.png?resizew=157)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/500d68f2678989a5ce7431cfd51b019d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e4125524caac016727c80d2722c5ba3.png)
(2)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1069d514c3c32aeabd274475ee209ed6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9bf506dfa47d0eca749b849f61820ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
您最近一年使用:0次