其反函数的定义域即为函数y=-3+log 2(x-1)(x≥5)的值域,由x≥5可得x-1≥4,log 2(x-1)≥2,y=-3+log 2(x-1)≥-1,
故函数y=-3+log 2(x-1)(x≥5)的值域为[-1,+∞),
故答案为[-1,+∞).
其反函数的定义域即为函数y=-3+log 2(x-1)(x≥5)的值域,由x≥5可得x-1≥4,log 2(x-1)≥2,y=-3+log 2(x-1)≥-1,
故函数y=-3+log 2(x-1)(x≥5)的值域为[-1,+∞),
故答案为[-1,+∞).