Task
If (a sub_n) and (b sub_n) are cauchy sequences, show directly that (a sub_n * b sub_n) is also a cauchy sequence.
Detailed explanation: NO
Specific requirements:
Prove
Prove: A subset S of the real numbers is closed if and only if lim (as n goes to infinity) X_n is an element of S whenever (X_n) is a convergent sequence whose terms are all in S.