Hi,
I'm struggling to prove that a limit ceases to exist as x tends to 0 for the following function:
$$f(x)=\begin{cases}\sin(\frac{1}{x}), & \text{if $x \notin \mathbb{Q}$} \\[3pt] 1, & \text{if $x \in \mathbb{Q}$} \\ \end{cases}$$
I've attempted a proof by contradiction, assuming the...