[填空题]
The function f is defin1hxx0jq,lb5evd6 gk )ed b qplmh0t.0n1 cjvgxdk)g/2 s/ iznj2- y , for , , where a \in \mathbb{R} . Part of the graph of y=f(x) is shown in the following diagram.
1. Find the largest value of a such that f has an inverse function.
2. For this value of a , find an expression for stating its domain