解题方法
1 . 在等差数列
中,若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bca8f26c7e2cf5c7c4eaf39b089ae52.png)
______
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fa4cf1aefcb569197b97ecb8fc4049f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bca8f26c7e2cf5c7c4eaf39b089ae52.png)
您最近一年使用:0次
名校
2 . 有一个由正整数组成的数阵排列如下表,则第60行的第一个数字是( )
1 | 2 | 4 | 7 | 11 | … |
3 | 5 | 8 | 12 | … | … |
6 | 9 | 13 | … | … | … |
10 | 14 | … | … | … | … |
… | … | … | … | … | … |
A.1770 | B.1830 | C.1999 | D.2019 |
您最近一年使用:0次
3 . 已知数列
的前
项和为
,且满足
.
(1)求数列
的通项公式;
(2)设
,
,
,求证:
.
![](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/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b7f96e0a6604b960b1cf02c95cef4e5.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcc84affaa5ee785ff8e8d4ef0ac1242.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/577a532c5b23f19c545178089389389c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a368aafd6b373058143f1593dd2f6e2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c3fec47d2dd2b8099d86c87b6e57de8.png)
您最近一年使用:0次
2020-03-20更新
|
542次组卷
|
2卷引用:2019届广西南宁市第二中学高三最后一模数学(理)试题
名校
解题方法
4 . 已知等差数列
的前
项和为
,且
,
.
(1)求数列
的通项公式;
(2)求使不等式
成立的
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6f35fa103e2d4cfb68dc624dc45608d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da7f12002611781ce9601baca8ae7ce3.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
(2)求使不等式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ade47598510917b18557339027024b69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
您最近一年使用:0次
2020-03-18更新
|
1290次组卷
|
4卷引用:2020届吉林省高三第二次模拟数学文科试题
名校
解题方法
5 . 已知数列
满足
,且
.
(1)求数列
的通项公式;
(2)求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b28deaf4cc144401929affe8f1b9945d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05c0a1a3f673d04b003333fec610edf3.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
(2)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/651fe803dbcc67154684746e884ae880.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
您最近一年使用:0次
2020-03-17更新
|
621次组卷
|
4卷引用:2020届广西壮族自治区钦州市第三中学高三下学期3月月考数学(文)试题
名校
6 . 已知等比数列
满足
,数列
是等差数列,其前
项和为
,且
,则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04582116cd765fcc5a52f44279ad6c94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ceea3d821604b0ed46e7e4b073b19537.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fce83115a50f99e08e9a2db7267aeed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/813212c49ff1aa099db88c562b46eca8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1aea87801b45e046721442c24cfbb1df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04582116cd765fcc5a52f44279ad6c94.png)
A.52 | B.26 | C.78 | D.104 |
您最近一年使用:0次
2020-03-17更新
|
529次组卷
|
4卷引用:2020届广西桂林市第十八中学高三上学期第二次月考数学(文)试题
名校
7 . 已知数列
是公差不为0的等差数列,且
,则
的前6项的和为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/351bb37f22b63cbca14fc83ed5bee1ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
A.30 | B.40 | C.50 | D.60 |
您最近一年使用:0次
8 . 在我国,9为数字之极,寓意尊贵吉祥、长久恒远,所以在许多建筑中包含了与9相关的设计.某小区拟修建一个地面由扇环形的石板铺成的休闲广场(如图),广场中心是一圆形喷泉,围绕它的第一圈需要9块石板,从第二圈开始,每一圈比前一圈多9块,共有9圈.问:修建这个广场共需要多少块扇环形石板?
![](https://img.xkw.com/dksih/QBM/2020/3/12/2418140562120704/2418558862147584/STEM/4de3ecd0-2f03-4bf8-bb68-8872bd7c39c3.png)
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9 . 已知数列
满足
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78b25dba51dcae67905c5f8aaa792337.png)
____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07404ab51f404f9411f79bd4f1fde654.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2279dad9128614e32e1b3446fbf336b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78b25dba51dcae67905c5f8aaa792337.png)
您最近一年使用:0次