解题方法
1 . “调和数列”被称为“和谐的数列”,在数学中的地位非常重要,广泛应用于音乐创作和建筑设计中.若数列
满足
(
为常数),则称数列
为“调和数列”.已知
为正项调和数列,
是
的前
项和,则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c697bf8d59f10fa93f6a535b4ded6e26.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b48b466ab970861ef47d1113d1146e51.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e30136113176ba7fe660e998d0873157.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
A.若![]() ![]() |
B.若![]() ![]() |
C.若![]() ![]() |
D.若![]() ![]() |
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解题方法
2 . 在
的展开式中,下列叙述中正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df47407b37a64b23e2a4a94901e2cc5f.png)
A.二项式系数之和为32 | B.各项系数之和为0 |
C.常数项为15 | D.![]() |
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3 . 某班级举行元旦文艺晚会,晚会有3个唱歌节目和2个小品节目,问:
(1)若2个小品节目彼此要隔开,有多少种排法?
(2)第一个节目和最后一个节目都是唱歌节目,有多少种排法?
(1)若2个小品节目彼此要隔开,有多少种排法?
(2)第一个节目和最后一个节目都是唱歌节目,有多少种排法?
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4 . 乘积式
展开后的项数是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/011d8e80756a0019e991cb2c1c295e98.png)
A.8 | B.9 | C.18 | D.27 |
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5 . 如图,三棱锥
的底面
和侧面
都是边长为2的等边三角形,
分别是
的中点,
.
平面
;
(2)求直线
与平面
所成角的正切值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41e5db1d2fd912f77923e4c120a7dc19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc9c9cfa597b444b5c9dbae7a825a695.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91e1e4115d78e625e9e0f47cdade3286.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dec2ca6438c82b43f746057d8129885.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/114328e2c6128710608977e7927c7a0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/963a91995abd4927d75406d16e10a81f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66e6629d0e1a4ce3fe4f0345f6961473.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34c157ff302a881c17514534903c575f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
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6 . 在四边形
中,
,则实数
的值为______ ,若
是线段
上的动点,且
,则
的最小值为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de4fec47150e684e8b270289048aff7f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d92b9548115581546be6f0a3c5a7057.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2ab157cd50abfa3a6de8027f3f0b424.png)
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解题方法
7 . 在
中,三个内角
所对的边分别为
.已知
的面积为
,
.
(1)求
的值
(2)求
的最小值.
![](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)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cf8c9594a0dc9767b5e84b9d55c5d03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24eb259fab57e11a4b98d4448a0e65fe.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6732580ffff616408c0985d7175a4c2.png)
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8 . 已知复数
满足
,则
的虚部为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e81e59019989b7dc2fb59b037ef6e010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/315f43e5af045f0a7e2195223630cd42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e81e59019989b7dc2fb59b037ef6e010.png)
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解题方法
9 .
与
的夹角为锐角,
的取值范围为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6fcec24159ada8e1d4caf18008a2137.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94075193c11fe43f2396cff5a485054.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
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10 . 如图所示,正方体
的棱长为1,线段
上有两个动点
,且
,则下列结论中正确的有( )
;
②三棱锥
的体积为定值;
③
的面积与
的面积相等;
④二面角
的正切值为
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cfbc0b5a8fbde804bd8425a4b76d207.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f115f2683c0422042f1846450885e7fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/589ddae20626f9aaac616d2a3b5d95bd.png)
②三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccc3bf74119692ac98eb24fcfa2a3f9f.png)
③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c105d6ba18fbb0581fb982175e2eac9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f2ea13010e2399194be2a681310543e.png)
④二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecd41f11a3360662c09b042a9f987e70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
A.1个 | B.2个 | C.3个 | D.4个 |
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