1 . 差分法的定义:若数列
的前
项和为
,且
,则
时,
.例如:已知数列
的通项公式是
,前
项和为
,因为
,所以
.
(1)若数列
的通项公式是
,求
的前
项和
;
(2)若
,且数列
的前
项和分别为
,证明:
.
![](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/314fa1f4da470780673cc7246974180c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0704f453b2de48d36911f7db496bbf82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9361afc7cc02253140585eedc39a695d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/677e46ecd051c92489c0d1d458932f37.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/e3bd2e55bb083a90ecba8cc98fac9536.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/237ce153a42d4e2378d5435051734cb3.png)
(1)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8bd845d1bfac72200926447db04563fc.png)
![](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)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77af844c4444e536adae9bc0b1cff614.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c04f062dc12653209868713f2142fe06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee1c51f15c934050099b460b19a04f4b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/038e3af7c9f2fb642b9209415662aeff.png)
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2024-05-30更新
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2卷引用:辽宁省朝阳市建平县高级中学2023-2024学年高二下学期期中考试数学试卷