“三角垛,下广,一面一十二个,上尖,问:计几何?”过去,商人们在堆放瓶瓶罐罐这类物品时,为了节省地方,常把它们垒成许多层,俗称“垛”,每层摆成三角形的就叫“三角垛”,“三角垛”自上而下,第1层1个,第2层(
)个,第3层(
)个,这样一道题目:用现在的话说,其意思就是:“有一个三角垛,最底层每条边上有12个物体,最上层只有1个尖),问:总共有多少个物体?”
(2)若用
表示第n层的物体个数,请做如下计算:
①
的值为多少;
②求数列
的前2024项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00860a6a9f7275e3d61e519b63802dd4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5c227f040ddfa79244fcac51bf9cef3.png)
(2)若用
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
②求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b01041691ad489f126f05c18ea8f0fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/addee6ce5163a2580888ce2da22714af.png)
更新时间:2024-05-28 14:03:27
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【推荐2】设Sn为等差数列{an}的前n项和,a6=11,公差d<3且a3+a7=a4a5﹣45.
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解答题-问答题
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名校
解题方法
【推荐1】已知正项数列
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(1)求
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(2)设
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(1)求
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