题目
题型：不详难度：来源：
| bc |
| a |
| ca |
| b |
| ab |
| c |
答案
| bc |
| a |
| ac |
| b |
| ab |
| c |
=（
| bc |
| a |
| ac |
| b |
| bc |
| a |
| ab |
| c |
| ac |
| b |
| ab |
| c |
≥2
|
|
|
=2c+2b+2a，
∴
| bc |
| a |
| ac |
| b |
| ab |
| c |
当且仅当a=b=c时，等号成立．
核心考点
举一反三
| n |
 |
| i-1 |
| n |
|
| i-1 |
| ab |
| bc |
| a |
| ca |
| b |
| ab |
| c |
| bc |
| a |
| ac |
| b |
| ab |
| c |
| bc |
| a |
| ac |
| b |
| bc |
| a |
| ab |
| c |
| ac |
| b |
| ab |
| c |
|
|
|
| bc |
| a |
| ac |
| b |
| ab |
| c |
| n |
|
| i-1 |
| n |
|
| i-1 |
| ab |
，可选择的方法有以下几种，其中最合理的是（ ）