解题方法
1 . 已知数列
是等差数列.
(1)若
,
,求
;
(2)若
,
,求
;
(3)若
,
,
,求n.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06dd3c3b45125d4b484e2894992610f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/455153a2e91379d95841db772c70db3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a34a901aa78366ac960f5f4e7f1fcbac.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/039e4fe671d61e59b96ee525c9df43e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad6d8a8a57db1c2fc7f465d2cfd2aa78.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f3cf6f2bbe20a404fea41a4d2b1c4c7.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ea8d0e50065114b05ef2dc1ea1129cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09ee990503e5b3608267fbd91cf16d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8000007201d28a54901c28b9feb6f62d.png)
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2 . 已知等比数列
中,
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cdc356c66227913f2332dcf592d0218.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7da2f386b78cdf6489efaa2f5820d3e.png)
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3 . 判断以下数列是否是等比数列?如果是,指出公比;如果不是,说明理由.
(1)1,10,100,1000,10000;
(2)0,1,2,4,8;
(3)
.
(1)1,10,100,1000,10000;
(2)0,1,2,4,8;
(3)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37261fac2e8e3f86bdaad7a6e8e99bcd.png)
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解题方法
4 . 已知等差数列10,7,4,….
(1)求这个数列的第10项;
(2)
是不是这个数列中的项?
呢?如果是,求出是第几项;如果不是,说明理由.
(1)求这个数列的第10项;
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54e60696d1c681628c57bb2c7e9d1814.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ab66291ef17f0d1664cefd6f6bffd31.png)
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5 . 已知数列
的通项公式为
,判断这个数列是否是等差数列.如果是,求出公差;如果不是,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/700f3c606fe413726ae0335825c2929c.png)
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6 . 已知等差数列
的公差为d,求证:对于任意的正整数m,n,有
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab4c1866153eb63162dba5c4e311a895.png)
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23-24高二上·全国·课后作业
解题方法
7 . 已知平面凸起边形
的内角和为
,若一凸n边形各内角的度数成等差数列,公差是10°,最小内角是100°,求n.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e30f0c33581d65209dbb0aaff67f55b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b161dcc1ab8044ae5daf010d320db651.png)
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23-24高二上·全国·课后作业
8 . 已知
,
为等差数列
的图象上的两点.
(1)求数列
的通项公式;
(2)画出数列
的图象;
(3)判断数列
的单调性.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/929a5a2d5fdcb44684f2408a251f1e66.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66ea9c86a4cc05d5c95c134edb874e7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)画出数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(3)判断数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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23-24高二上·全国·课后作业
9 . 设
,
,
,
是等差数列
的项,且
.求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f255d0395fba51ca2d44293cca42e0a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f84aac9ff61204b05af0202c322ca3e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/681ae1522a36768618f7ddaf74abbb7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6487ee14d2f12567f230cd4a29353ad2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19a57606818bb756dc253c0099948be4.png)
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