1 . 如图,在棱长为
的正方体
中,M,N,P分别是
,
,
的中点,则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f66fb71b75b63594ebeeeebd1963eed5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53e97fcdcfd6183b976a61ef3222c607.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a696a182fff038a86b2bbe8ca099442.png)
A.M,N,B,![]() |
B.若![]() ![]() ![]() |
C.平面PMN截正方体所得截面为等腰梯形 |
D.若![]() ![]() ![]() |
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解题方法
2 . 已知
.
(1)求
的值;
(2)求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02a2f6d370ed6f1d6582251c6e1bad62.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/850dba25bf0f5f13541bf9b6ec12b84d.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63fe57d4fbae536de2e641d9d349fcf1.png)
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3 . 如图,在平行四边形
中,
,垂足为P,E为
中点,
·
=32,求
的长;
(2)设|
|=
,|
|=
,
=-
,
=x
+y
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfbad7ad1465d1c4c177e3321e6ed12a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7239b3f2d88c2e45e17e5de9ae1a332.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af5f1b06a56fc382feed28e01f1ad102.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
(2)设|
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abcb5d89b04570ceda2c29e11cb27a57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af5f1b06a56fc382feed28e01f1ad102.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2967337e3fcb228dded64ab0c41a17e0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3acf551f38311eccdcc325c0d283473.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d83fb9ac8a18e78a4c56da79514b5ccb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7239b3f2d88c2e45e17e5de9ae1a332.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d021a5c98388463d577675e58068aa7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af5f1b06a56fc382feed28e01f1ad102.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f29d5f376c75c41ae6af0c8a8565449.png)
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解题方法
4 . 已知
内角
对边分别为
,则下列说法正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e428e7a09732be85c1224e9c8f6a71c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/516983449108347c9bbf5dd2a72ab3dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d90d7f054e8f0346479e1999622f11cf.png)
A.若![]() ![]() |
B.若![]() ![]() |
C.若![]() ![]() |
D.若![]() |
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解题方法
5 . 在
中,角A、B、C所对的边分别为a、b、c,
,
是
的中线,且
,则
的最大值为_______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e918b70b02a73685e3c536c7f380e2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dfb08f6a798dc293f3d8de281190f65e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd1810555c0c28fe352841322b85bbc6.png)
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解题方法
6 . 在
中,角A,B,C对边分别为a,b,c.若
,
,
,则实数a的值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e428e7a09732be85c1224e9c8f6a71c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eec0381f33580f362fa0a44507d9c3d6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/656acdefb64a975d660e2c25aabbf602.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2509871b0a1c0065e0c5fe33e5f56247.png)
A.6 | B.3 | C.![]() | D.![]() |
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7 . 如图,在四面体
中,
平面
,
,
,点
在线段
上.
是线段
中点时,求
与平面
所成角的正弦值;
(2)若二面角
的余弦值为
,求
的值.
![](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/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36c4559d27e3905980d1a4f1856f07de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba924d427bf2df79144e2611f50ad00f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f571a1aac46c6d0cf440c0ec2846bf9.png)
(2)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad6a0cee8226e82cc57916e10d533369.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dac452fbb5ef6dd653e7fbbef639484.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d8c176e0c2b435675a3b8efab0e498d.png)
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8 . 在二项式
的展开式中,第5项和第6项的二项式系数相同,
(1)求所有偶数项的二项式系数的和;
(2)求各项系数绝对值之和.
(3)若记
,求展开式中
中取最大项时
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e68fb64e252a20d360cf890d9603a181.png)
(1)求所有偶数项的二项式系数的和;
(2)求各项系数绝对值之和.
(3)若记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f826552f5b0546132e7c0b72bfd4b8dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/857641f5cae585bd4655193270a7dae7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
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9 . 某机构组织举办经验交流活动,共邀请了八位专家,以
区分,现安排专家发言顺序,则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/834e7d318fd832c73f1065259d62d988.png)
A.![]() ![]() ![]() |
B.![]() ![]() ![]() |
C.![]() |
D.![]() ![]() ![]() |
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名校
解题方法
10 . 为普及安全知识,某单位举办了一场安全知识竞赛,经过初赛、复赛,有甲、乙两个代表队(每队三人)进入决赛,决赛规则如下:共进行三轮比赛,每轮比赛中每人各答一题,每答对一题得 10 分,答错不得分. 假设甲队每人答题正确的概率均为
,乙队三人答题正确的概率分别
.
(1)若决赛中三轮总得分大于70分就能获得特别奖,求乙队获得特别奖的概率;
(2)因两队在决赛中得分相同,现进行附加赛. 规则如下:甲,乙两队抽签决定谁先答题,每队每人各答题一次为一轮,有两人及以上答对就算成功答题,并继续下一轮答题,否则换另一队答题,连续两轮成功答题的队伍获胜,比赛结束. 求附加赛中甲队恰好在第5轮结束时获胜的概率.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3783f11b078c7b7262f28e2e90bf334.png)
(1)若决赛中三轮总得分大于70分就能获得特别奖,求乙队获得特别奖的概率;
(2)因两队在决赛中得分相同,现进行附加赛. 规则如下:甲,乙两队抽签决定谁先答题,每队每人各答题一次为一轮,有两人及以上答对就算成功答题,并继续下一轮答题,否则换另一队答题,连续两轮成功答题的队伍获胜,比赛结束. 求附加赛中甲队恰好在第5轮结束时获胜的概率.
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