(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Prove that {(a1, a2) ∈ R2 : 0 ≤ a1 ≤ 2, 0 ≤ a2 ≤ 4} is a closed set in the Euclidean metric.

2. Relevant equations

Not sure

3. The attempt at a solution

How do I approach this problem? Do I prove there is a closed ball in my set? Or, do I prove there is an open ball in the complement of my set which makes my complement open which makes my set closed? Or, is there a better way to do it using union/intersections of open/closed sets?

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# Prove this is a closed set/Real Analysis

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