(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?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Prove this is a closed set/Real Analysis

**Physics Forums | Science Articles, Homework Help, Discussion**