问题
选择题
等差数列{an}，{bn}的前n项和分别为Sn，Tn，若
|
答案
∵
| an |
| bn |
| 2an |
| 2bn |
| a1+a2n-1 |
| b1+b2n-1 |
| ||
|
| s2n-1 |
| T2n-1 |
∴
| an |
| bn |
| 2(2n-1) |
| 3(2n-1)+1 |
| 2n-1 |
| 3n-1 |
故选B．
搜题请搜索小程序“爱下问搜题”
等差数列{an}，{bn}的前n项和分别为Sn，Tn，若
|
∵
| an |
| bn |
| 2an |
| 2bn |
| a1+a2n-1 |
| b1+b2n-1 |
| ||
|
| s2n-1 |
| T2n-1 |
∴
| an |
| bn |
| 2(2n-1) |
| 3(2n-1)+1 |
| 2n-1 |
| 3n-1 |
故选B．