Answer:
2n < x < 2n+1 . . . . for any integer n
Explanation:
The function is only defined where sin(πx) is positive, so x will be between 0 and 1 (not inclusive). The pattern repeats for (2, 3), (4, 5), (6, 7), and so on.
The domain is (2n, 2n+1) for any integer n.