In: Advanced Math
Let A be a subset of all Real Numbers. Prove that A is closed
and bounded (I.e. compact) if and only if every sequence of numbers
from A has a subsequence that converges to a point in A.
Given it is an if and only if I know we need to do a forward and backwards proof. For the backwards proof I was thinking of approaching it via contrapositive, but I am having a hard time writing the proof in a way that is understandable to the readers.