已知${a_n}$满足$a_1=1,a_{n+1}=(1+\frac{1}{n^2+n})a_n.$证明:当$n\in N^+$时, $(1)a_{n+1}>a_n.(2)\frac{2n}{n+1}\le a_n\le \frac{en}{n+1}$ 评:当然也可以按参考答案由数学归纳法证明. 相关文章: 2022-12-23 2022-12-23 2022-12-23 2023-03-18 2022-12-23 2022-12-23 2022-12-23