解题方法
1 . 如图,正三棱柱的所有棱长都为
,
为
中点.用空间向量进行以下证明和计算:
(1)求证:
平面
;
(2)求二面角
的正弦值;
(3)求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/15/f870e198-8909-4c0c-8801-254d09411b09.png?resizew=180)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4560fa4ad459b58b723c74bd24e51ebf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7935fe3125f247b7bea4f065ce9ad985.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f97babc2abb18c1540d3a5504f7cf3fe.png)
(3)求点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7935fe3125f247b7bea4f065ce9ad985.png)
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名校
2 . 利用分析法证明是从求证的结论出发,一步一步地探索保证前一个结论成立的( )
A.必要条件 | B.充分条件 | C.充要条件 | D.必要条件或充要条件 |
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2023-01-17更新
|
42次组卷
|
2卷引用:陕西省米脂中学2021-2022学年高二下学期第一次月考数学(理)试题
名校
解题方法
3 . 如图所示,四棱锥
的底面是边长为1的正方形,
,E为
上一点,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/16/d5a2014a-22ca-4d3a-bcd3-26bf77127c50.png?resizew=154)
(1)求证:
平面
;
(2)在侧棱
上是否存在一点F,使得
平面
?若存在,指出F点的位置,并证明;若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e896ec179a48561a0671416340ddfc10.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afcbbbe350b38381d1999e2886d45f0e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/16/d5a2014a-22ca-4d3a-bcd3-26bf77127c50.png?resizew=154)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)在侧棱
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9d32e76582bf550593fdef53e081225.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46e2da608b66c9aee03e2503388ba4fd.png)
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2022-09-15更新
|
1841次组卷
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5卷引用:陕西省渭南市华州区咸林中学2022-2023学年高三上学期第二阶段考试理科数学试题
解题方法
4 . 如图1,已知正方形
的边长为
,
,
分别为
,
的中点,将正方形
沿
折成如图2所示连结
,且
,点
在线段
上(包含端点)运动,连接
.
![](https://img.xkw.com/dksih/QBM/2022/5/14/2979121362894848/2980612692860928/STEM/b022c895-be02-462b-8691-fb608bd85486.png?resizew=396)
(1)若
为
的中点,直线
与平面
的交点为
,试确定点
的位置,并证明直线
平面
;
(2)点
为
的中点,求证
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67d822262ff00915910e5b87d81ad1ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ff635d2c15b5b477ee33d7d2bfe4408.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://img.xkw.com/dksih/QBM/2022/5/14/2979121362894848/2980612692860928/STEM/b022c895-be02-462b-8691-fb608bd85486.png?resizew=396)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/907d5147cea4c9ce855074864fe54506.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6072ec6dfc0203cabb1fe289a5ddc8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/558ce69401f3c97930f00ba0e2aa6647.png)
(2)点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06ade1ccd464353eb8ceeb312339dc14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/369eb8ad56da7dc1cdb7c43762be4bee.png)
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5 . 用综合法或分析法证明以下问题:
(1)若
是互不相等的实数,且
,求证:
.
(2)已知
.求证:
.
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a14c388e1e2e5a2ff1ccf6caffbee0d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/baa4b450e9269a7ef67582e7359f0125.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27b2d4c175ae8fadf2da3078ec2904d4.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fd185d0e487fab58f8b0bfbb46e4ba7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba77de7002cfcd4ae007a3c8b813e3b0.png)
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2022-05-12更新
|
134次组卷
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2卷引用:陕西省宝鸡市金台区2021-2022学年高二下学期期中理科数学试题
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6 . 用分析法证明:已知
,且
求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9592180b3752b8ace79e7b92f98cec1b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5be97cd1c7111b654d87d8fbb63b6a84.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2533c09d4efe229490a509902d812566.png)
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7 . (1)求证:
;
(2)已知
,
,且
,用反证法证明:
和
中至少有一个小于2.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94b3d03b6098d2f3f30d213d830d6a84.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94440d3e4c073f94f2b266ff99d50e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67ca5fd57c2c2fcc3c7a574fdd1467d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69bbd0aae5a4f6129fc78f88f662f092.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5360e1dce424ae202f4ca4e5b842499f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/361751a03c628b8ddb0952a7390f7810.png)
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2021-10-13更新
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4卷引用:陕西省西安市鄠邑区第一中学2021-2022学年高二下学期第一次月考文科数学试题(B卷)
名校
解题方法
8 . 在
中,角
的对边分别为
.
(1)求证:
中至少有一个角大于或等于
;
(2)若角
成等差数列,证明
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d5bca00fa20e6e80480b9d06d2e52ee.png)
(2)若角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/369b284e4ea67a49d996312409064823.png)
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2021-08-01更新
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409次组卷
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2卷引用:陕西省咸阳市实验中学2021-2022学年高二下学期阶段性检测(一)数学(理)试题
名校
解题方法
9 . 如图所示,已知点P是平行四边形
所在平面外一点,M,N,Q分别
,
,
的中点,平面
平面
.
![](https://img.xkw.com/dksih/QBM/2021/12/15/2873155538780160/2873622982402048/STEM/053f9d3b-61ac-46be-a07a-5526077134ff.png?resizew=335)
(1)证明平面
平面
;
(2)求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a09d03d26008b17d89e98125eff110c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4d19526cadbce0e984c2edc3f31d591.png)
![](https://img.xkw.com/dksih/QBM/2021/12/15/2873155538780160/2873622982402048/STEM/053f9d3b-61ac-46be-a07a-5526077134ff.png?resizew=335)
(1)证明平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79b28a07491270be75a3697538bec706.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edbf6462666c8015e7de28e344af30b2.png)
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2021-12-16更新
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4卷引用:陕西省延安市黄陵中学2021-2022学年高一上学期期末数学试题
陕西省延安市黄陵中学2021-2022学年高一上学期期末数学试题陕西省西安中学2021-2022学年高一上学期12月第二次月考数学试题(已下线)8.5 空间直线、平面的平行(已下线)第08练 点线面的位置关系-2022年【暑假分层作业】高一数学(苏教版2019必修第二册)
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10 . 利用反证法证明“已知
,求证:
中,至少有一个数大于20.”时,首先要假设结论不对,即就是要假设( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7267291073b77eab69d5d01383c045d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/874781ab5711bff6ee8c9cbad5b3b3dc.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
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