1 . 如图,已知平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
平面
,
与
分别是棱长为1与2的正三角形,
//
,四边形
为直角梯形,
//
,
,点
为
的重心,
为
中点,
.
![](https://img.xkw.com/dksih/QBM/2016/11/22/1573167655288832/1573167661498368/STEM/0cf6f921b91a40898df3ad2dc873ba7f.png?resizew=222)
(Ⅰ)当
时,求证:
//平面
;
(Ⅱ)若直线
与
所成角为
,试求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fa7bbd7831e9ff4f8cffc8889d34f05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3634979dfcebf857b20874dd320d80b3.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/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fa7bbd7831e9ff4f8cffc8889d34f05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89f1caa74921b9af5a0443edc45c6788.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85be66eadf9e42bf682ab1d827b6ca10.png)
![](https://img.xkw.com/dksih/QBM/2016/11/22/1573167655288832/1573167661498368/STEM/0cf6f921b91a40898df3ad2dc873ba7f.png?resizew=222)
(Ⅰ)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/441809d6ce2df21a85b390cdce9b1112.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e9e953a4a5f98c96bbe67cbaadf76d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6895da13331cb525f5850d7b7a02a847.png)
(Ⅱ)若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d88591679796c52024d11c4de641bdb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0a8e0c5bcf2d86726cd9f561b8ff5fe.png)
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浙江省丽水四校联考2019-2020学年高三9月阶段性考试数学试题(已下线)2011-2012学年浙江省温州市温州中学高三下学期第三次理科数学试卷2017届浙江温州中学高三10月高考模拟数学试卷江西省景德镇一中2017-2018学年高二上学期期末考数学(理)试题
11-12高三·浙江·阶段练习
名校
2 . 三棱锥
中,
两两垂直且相等,点
,
分别是
和
上的动点,且满足
,
,则
和
所成角余弦值的取值范围是 .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4278c0911e7df78965e78cff69cac5f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84c83984c62d390c6b30efa5d4e560de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a28b6d5ede0345186aea36bd2ee0647.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e35e438fcd14688a7e59f9a3ee71e47c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
您最近一年使用:0次
2016-12-01更新
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4卷引用:浙江省丽水四校联考2019-2020学年高三9月阶段性考试数学试题
浙江省丽水四校联考2019-2020学年高三9月阶段性考试数学试题(已下线)2012届浙江省高三第二次五校联考理科数学试卷2017届浙江温州中学高三10月高考模拟数学试卷浙江省宁波市余姚中学2017-2018学年高二(宜张班)上学期第一次质量检测数学试题