The function is:
f(x) = 3√x - 1
The domain of the function is the set of all values of x for which the function is defined. In this case, the function is defined only for non-negative values of x, since the cube root of a negative number is not a real number. So, the domain of the function is:
x ≥ 0
The function takes a non-negative input, takes the cube root of it, multiplies the result by 3, and then subtracts 1. The output of the function is a real number.