Answer:
(-∞, α)
Explanation:
The domain is the set of all possible x-values that will make the function work.
f(x) will exist only if the radicand is positive.
Also, x cannot equal α, because f(α) = 1/√0 =1/0 = undefined. Thus, we must have
α - x > 0 or
x < α
The domain is x <α.
In interval notation, the domain is (-∞, α).