1.
Let f(x)=x2f(x)=x^2, x∈Rx\in\mathbb R. For any A⊆RA\subseteq\mathbb R, define g(A)={x∈R:f(x)∈A}g(A)=\{x\in\mathbb R: f(x)\in A\}. If S=[0,4]S=[0,4], then which one of the following statements is not true?