题干
函数f（x）对任意正整数a、b满足条件f（a+b）=f（a）•f（b）且f（1）=2，则
+
+
+…+
的值是____．
| f |
| ( |
| 1 |
| ) |
| f |
| ( |
| 2 |
| ) |
| f |
| ( |
| 2 |
| ) |
| f |
| ( |
| 3 |
| ) |
| f |
| ( |
| 3 |
| ) |
| f |
| ( |
| 4 |
| ) |
| f |
| ( |
| ) |
| f |
| ( |
| ) |
答案(点此获取答案解析）
1008
