Piecewise Functions - Explanation, Finding Domain, and FAQs - VEDANTU Now, let's find the domain and range of a piecewise function adding the restrictions in the 'if' statements: Like we said earlier, the quadratic just looks like less than zero (<0), the linear only looks like from 0 to 3, and the constant only appears followed by 3, thus: Domain: (−∞, ∞) Range: (0, ∞)