| 计算:2-22-23-…-22006+22007 |
答案:
| ∵22007-22006=22006(2-1)=22006,22006-22005=22005(2-1)=22005…, ∴2n+1-2n=2n(2-1)=2n, ∴原式=22007-22006-…-23-22+2 =22006(2-1)-22005-23-22+2 =22005(2-1)-22004-23-22+2 =22+2 =6. |

| 计算:2-22-23-…-22006+22007 |
答案:
| ∵22007-22006=22006(2-1)=22006,22006-22005=22005(2-1)=22005…, ∴2n+1-2n=2n(2-1)=2n, ∴原式=22007-22006-…-23-22+2 =22006(2-1)-22005-23-22+2 =22005(2-1)-22004-23-22+2 =22+2 =6. |