Problem 29. Let (X, F ) be a topological space and A, B C X. (a) Prove or disprove Int(AUB) = Int(A) UInt(B). (b) Prove or disprove Int(AnB) = Int(A) nInt(B). (c) Prove or disprove A UB = AUB. (d) Prove or disprove AnB = AnB