Question

Let \(f:X\rightarrow\mathbb{R} \)be a continuous function on a metric space \(X \)and\(
\quad a, b \in \mathbb{R}\). Prove in a way similar to the proof in the lecture (using the pre image criterion)
d) \(V := \{x \in X : |f(x)| > 1 \} \subset X\) is open