
19.(本小题满分12分)已知数列{an},{bn}满足a1=9,an 1=10an 9,bn,=an 1.
(1)证明:{bn}是等比数列;
(2)求数列{(-1)”lgbn}的前n项和Sn.
作者:网络 来源: 2022-04-13 15:30:27 阅读:次
19.(本小题满分12分)已知数列{an},{bn}满足a1=9,an 1=10an 9,bn,=an 1. (1)证明:{bn}是等比数列; (2)求数列{(-1)”lgbn}的前n项和Sn.
19.(本小题满分12分)已知数列{an},{bn}满足a1=9,an 1=10an 9,bn,=an 1.
(1)证明:{bn}是等比数列;
(2)求数列{(-1)”lgbn}的前n项和Sn.