23-24高二上·上海·课后作业
名校
1 . 已知等差数列
,
,
,….
(1)求该等差数列的第20项.
(2)试问
是不是该等差数列的项?如果是,指明是第几项;如果不是,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d13ce3ebd1112220c639562739f1f9d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3aab28a20b5bf47040aaec03b1eb550.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77424dbdd740737b4ec75d62cdd08b27.png)
(1)求该等差数列的第20项.
(2)试问
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba4d49146f9d6c8b29896fc49b408e2e.png)
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23-24高二上·上海·课后作业
解题方法
2 . 已知数列
均为等差数列.
(1)设
,
,求
;
(2)设
,
,求
;
(3)设
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96c41befd9ad431dc8cd0df351b51080.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89b24e22503480d88ec847c9bc1be5d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7eed39c7d611309b01476c15ab242308.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4505b198b380fb022f9fd7bdc0a5950.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c57b14334c35386bf8db7d777446d54d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194592cb77de8a597d5d64e1c85c3249.png)
(3)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a0d29f34218cd60cc6e9ce4dcd13925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194592cb77de8a597d5d64e1c85c3249.png)
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23-24高二上·上海·课后作业
解题方法
3 . 已知数列
的前
项和为
.
(1)求数列
的通项公式;
(2)求证:数列
是等差数列.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57c599e7cec6d192fb73218e7882ceca.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)求证:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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23-24高二上·上海·课后作业
4 . 在等差数列
中,
(1)已知
,
,
,求
;
(2)已知
,
,
,求
;
(3)已知
,
,求
;
(4)已知
,
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/039e4fe671d61e59b96ee525c9df43e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f2572192cc7ca046e9a3155ef3e56a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe08722cf9300fe188dbbb71989c06c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b13a6e1d671215fc96e4bee3541d1096.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3c636f422a3b076c708480f979aa8ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5c1344592c925b273f2cb9b9e47ebbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
(3)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8827c05075967f3c3569d31cb6b83919.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e91ce5faf26829c7a4909006eeb9a7b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
(4)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3e2f2e4ec975aabd9fc243499cbb49e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ff6de1ee895470114429ac01726f405.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
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23-24高二上·上海·课后作业
解题方法
5 . 判断下述命题甲是命题乙的什么条件:
(1)命题甲:
,
,
是等差数列;命题乙:
.
(2)命题甲:三角形
中有大小为
的内角;命题乙:三角形
的三个内角的度数经适当排列后可以构成一个等差数列.
(1)命题甲:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/837e6496bb3e3ec09b0b69db71399ac2.png)
(2)命题甲:三角形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
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23-24高二上·上海·课后作业
6 . 已知数列
是等差数列,
(1)若
,
,求
;
(2)若
,
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/630df1e98d73e9c43bd8378991534dd6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8c8c5814586583244aecf6946b7cd40.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7eed39c7d611309b01476c15ab242308.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/630df1e98d73e9c43bd8378991534dd6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/becc70ab358907198a774868bb8d7478.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/973d17cd50a4905164d29b8449fafd52.png)
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23-24高二上·上海·课后作业
解题方法
7 . (1)在等差数列
中,是否
都成立?
(2)在数列
中,如果对于任意的正整数
,都有
,那么数列
一定是等差数列吗?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3bf44f095ce186d4aa35516ee7f86055.png)
(2)在数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4f27f84764f1cca89ce3d93fc1cf603.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15f50529572e9f1e00e6c4007df0b2d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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23-24高二上·上海·课后作业
8 . 假设体育场一角看台的座位从第2排起每一排都比前一排多相等数目的座位.若第3排有10个座位,第9排有28个座位,则第12排有多少个座位?
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23-24高二上·上海·课后作业
解题方法
9 . 已知数列
的前
项和为
,求证:数列
是等差数列.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82c662d8f38a824e3c9c2e26a7828a9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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23-24高二上·上海·课后作业
10 . 在等差数列
中,
(1)已知
,
,求
,
;
(2)已知
,
,求
;
(3)已知
,
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0e4dee6496d38112bf21e5819c8da8b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53572b203bf36a9461dc9a744367a4d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6278d3cc0086c7aab6ac20712c7d0bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a96d4cc6af7cfdb3d3a377f8e24b59ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e35eeaabd951fb09b2926807da3685b.png)
(3)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a71e56f374084c51b0b761c14d750dae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a0d29f34218cd60cc6e9ce4dcd13925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc858b7a95c5006a44067022da09f667.png)
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