题干
已知函数f（x）= {2sinπx，x<1 f(x−
)，x≥1
) =____．
| 2 |
| 3 |
| f |
| ( |
| 2 |
| ) |
| f |
| ( |
| 1 |
| 6 |
答案(点此获取答案解析）
﹣ 3
