Homework Statement
Where ##a,b\in \mathbb{R}##, show that ##[a,b)## is not open.
Homework EquationsThe Attempt at a Solution
I need to show that there exists an ##x\in [a,b)## such that for all ##\epsilon > 0##, ##B_\epsilon (x) \not \subseteq [a,b)##. To this end put ##x=a##, and let...