Mathematics 220
Homework for Week 4
This set will not be collected
Problems from Chapters 3 and 4 of the 3rd edition of the text.
• 3.2, 3.8, 3.14, 3.18, 3.22, 3.26
• Prove the implication: if m, n ∈ Z are odd then m2 + 3n2 is even. What is the converse
of the implication? Is the converse true or false? Justify your answer.
• 4.2, 4.10, 4.18, 4.22 (a)(d)(e)
• 4.42, 4.48, 4.56
• Let A, B be two sets. Prove: If A ∩ B = ∅ then A = (A ∪ B)\B.
If you are using the 2nd edition, be careful — question numbers may not agree.