2024高二下·北京·专题练习
解题方法
1 . 北京天坛的圆丘坛为古代祭天的场所,分上、中、下三层.上层地面的中心有一块圆形石板(称为天心石),环绕天心石砌9块扇面形石板构成第一环,向外每环依次增加9块.下一层的第一环比上一层的最后环多9块,向外每环依次也增加9块.已知每层环数相同,且上、中下三层共有扇面形石板(不含天心石)3402块,则中层共有扇面形石板( )
![](https://img.xkw.com/dksih/QBM/editorImg/2024/6/19/b2c4d673-9d2d-4325-aa5f-d71bab93ca33.png?resizew=185)
A.1125块 | B.1134块 | C.1143块 | D.112块 |
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13-14高一下·重庆·阶段练习
2 . 将一个等差数列依次写成下表:
第1行:2
第2行:5 8 11
第3行:14 17 20 23 26
………………………………………………
第
行:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30e843a95617ad24ea4e789a0cdc5912.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68c82be573157fd2c8068cb000505b43.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4aec8aa05d77a638e99494af9dfc0896.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/907e338a2cd8381353173126753e2415.png)
………………![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a2814549b2e9f30007ab2d811dd9adf9.png)
(其中
表示第
行中的第
个数)
那么第
行的数的和是_________________ .
第1行:2
第2行:5 8 11
第3行:14 17 20 23 26
………………………………………………
第
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30e843a95617ad24ea4e789a0cdc5912.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68c82be573157fd2c8068cb000505b43.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4aec8aa05d77a638e99494af9dfc0896.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/907e338a2cd8381353173126753e2415.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/392546a6637cb8faf9f356f4739cd7e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a2814549b2e9f30007ab2d811dd9adf9.png)
(其中
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee641d39bc70aa40e611fcfc6b78f30b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c05b9832b09731a574d4a4adf7448de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7600d2cfbdc6146db96cc545706004f6.png)
那么第
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
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