Help me please! Calculus - Theorem

Question

Determine the interval on which f(x) =  is integrable

Options:

1. [-∞, 3)
2. [0, ∞)
3. [3, ∞)
4. All reals

Answer 1

f(x) = √(x-3) is integrable as long as x - 3 ≥ 0. So, when x ≥ 3.