题干
如果函数f ( x ) =
，则lim
的值等于____．
| 1 |
| x |
| f |
| ( |
| 4 |
| + |
| x |
| ) |
| - |
| f |
| ( |
| 4 |
| ) |
| x |
答案(点此获取答案解析）
| 1 |
| 1 |
| x |
| f |
| ( |
| 4 |
| + |
| x |
| ) |
| - |
| f |
| ( |
| 4 |
| ) |
| x |
| 1 |
