Consider the following two sets: A-() B-0- A= n=1 Prove that if x > 0 or x < 0, then x # A. Prove that 0 A, and thus A = {0}. Is this an open set? A closed set? Prove that if x 1 or x 0, then x # B. Prove that if x (0, 1) then x B, and therefore B = (0, 1).