1 . 在①
,②
,③
,这三个条件中任选一个补充在下面的横线上,并加以解答.
在
中,角
,
,
所对的边分别为
,
,
,且 .
(1)求角
的大小;
(2)若
为锐角三角形,
,求
面积的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ef8ad9f9cf060771d47d36cde93afae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5455c52de0aef08eba4c104f99efeab6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/949400f9ba875a3e230063573a423e74.png)
在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
(1)求角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8120119749d4bc28067e73fca7d46cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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解题方法
2 . 已知
,
,且
,
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/481e744af0f65e797a35d976c20f2dac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3cd71803df3c72c63ee5fe30661b1a1f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d61e2e7cc4834161983649bfac47d872.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f69b1edea06acefd1b2347de4f7721.png)
A.![]() ![]() | B.![]() ![]() | C.![]() | D.![]() |
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解题方法
3 . 已知一个平面内的三个向量
,
,
,其中![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9feedc68e0c2d1b0de51d28e61496e59.png)
(1)若向量
为单位向量,且与
共线,求向量
的坐标;
(2)若
,且
与
垂直,求向量
与
的夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23bd18136e4e71e1e267bc9f8634b932.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec82bd4e0fb7887e5999b8220f60b073.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ecf646bc2e4cdd46fc5cc40d741dab5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9feedc68e0c2d1b0de51d28e61496e59.png)
(1)若向量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ecf646bc2e4cdd46fc5cc40d741dab5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23bd18136e4e71e1e267bc9f8634b932.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ecf646bc2e4cdd46fc5cc40d741dab5.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5404940e86fc3db18adcb5be78e2e276.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59feec0a253476e1baa7ac2d196da24c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abb1d6b61205267d523c5cab8ac68cf5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23bd18136e4e71e1e267bc9f8634b932.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec82bd4e0fb7887e5999b8220f60b073.png)
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解题方法
4 . 如图所示,在直三棱柱
中,若
,
,则下列说法中正确的有( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6c02338caa8ea2a27a5a37226a8a472.png)
A.三棱锥![]() ![]() |
B.点![]() ![]() ![]() ![]() |
C.![]() ![]() ![]() ![]() ![]() ![]() ![]() |
D.点![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
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5 . 已知a,b,c分别为
内角A,B,C的对边,下面四个结论正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
A.若![]() ![]() |
B.在锐角![]() ![]() |
C.若![]() ![]() ![]() ![]() ![]() |
D.若![]() ![]() ![]() ![]() |
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解题方法
6 . 已知非零平面向量
,
的夹角为
,且
,则
的最大值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94075193c11fe43f2396cff5a485054.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac1a63ab608517bb10aa036783dfb51f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c749bf931067fe018d6c0cd1f1d17c96.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1df935fa012bba7c0e920776ed24f56b.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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7 . 如图,在三棱锥
中,
平面
分别为棱PC,PB的中点.
平面
;
(2)若
,求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/517f89f30121be4d53d6aee05fccf044.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d077f6da8b2c00b152d4679aa2ed7f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/587df01a98f499a9f361aafd8c3dac39.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5617a404c5a3356753136e5a6b6d51e5.png)
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8 . 在正四棱台
中,
,且该四棱台的体积为
,则下列说法正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d134433600df75f2a5d0f35deb2cac90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7054c60c3472ee4dc7b5ea5a8d6b1b6a.png)
A.![]() |
B.该四棱台的表面积为32 |
C.直线![]() ![]() ![]() |
D.直线![]() ![]() ![]() |
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9 . 如图①,矩形ABCD中,
,
,E,F分别为AB,DC的中点.将四边形AEFD沿EF折起至四边形
的位置,如图②.
在平面
上的射影为
的中点,则三棱锥
的体积为________ ;
(2)当平面
与平面
垂直时,作正方体
如图③.若平面
平面
,且平面
截该正方体所得图形的面积记为
,则
的最大值为________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d27bd71d79cb19eb554175e4ef0867.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6ccd49a0c3ccd22943c15ed7bf0f4c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a03952d664fba91020fc5f3bcf2f9746.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/945fbe95bfb4e8e37e619e2d767efef6.png)
(2)当平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6ccd49a0c3ccd22943c15ed7bf0f4c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a03952d664fba91020fc5f3bcf2f9746.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0bc49d40da6aebbb370be30fa2e6c06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/414844edd458857bdfc80bffa61cbf9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecba239ca1f109309bf14fab784ea827.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf231f8f86fb922df4ca0c87f044cec3.png)
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解题方法
10 . 已知
和
都是直角三角形,
,E,F分别是边AB,AD的中点,现将
沿BD边折起到
的位置,如图所示,使平面
平面BCD.
平面BCD;
(2)求证:平面
平面
;
(3)请你判断,
与BD是否有可能垂直,做出判断并写明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/661ff55b5ebbadfb600989af3cfce2fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5ff103699fefbd87327b26b58fafd42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07c967c9b3f669ea78edd838e1d8b59e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba0fbd88fdb064072eedd136e9cb41ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57f9d682e5d3cc8573574d8d11636758.png)
(2)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21dee56b9f36ba8f76fe67b76383636b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74bca84ad86c648d3bb20c8909c8da3f.png)
(3)请你判断,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
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