Concept:A square root function f(x)=g(x) is defined only when g(x)≥0.Explanation:The given function is f(x)=1−(x−1)2.For it to be defined, the expression under the square root must be non‑negative:1−(x−1)2≥0.Rearrange: (x−1)2≤1.Taking square roots on both sides (since both sides are non‑negative):−1≤x−1≤1.Add 1 to all parts: 0≤x≤2.Thus the domain is the closed interval [0,2].Answer:[0,2]