Domain is what x can be so see what could possibly cause a problem.

For one, you can't have a 0 on bottom of a fraction so x can't be 2. And, you can't square root a negative so x can't be less than 0.

That makes the domain be all numbers greater than or equal to zero, except for 2. Interval notation:

[0, 2) U (2, ∞)

For the numerator to not be imaginary, we need x >= 0.

For the denominator to not be 0, we need x ╪ 2.

Therefore the domain is [0, 2) U (2, ∞).