1. The problem statement, all variables and given/known data I constructed my own question to try to make sense of the following notation. g(x) = 2√x g : X → Y. What does X and Y equal? 2. Relevant equations For 2√x, x = or > than 0. 3. The attempt at a solution g(x) = 2√x g : [0, ∞) → [0, ∞) So X = Y = [0, ∞) The reason why I am doing this is because my book shows this: g(x) = 2√x g : [1,∞) → [2,∞). Why does my book have a 1 instead of a 0 as an initial x value?