Lecture 5 (Discrete Math 2020)

By definition, the union A ∪ B is:

1. A.The set of all x such that x ∈ A or x ∈ B
2. B.The set of all x such that x ∈ A and x ∈ B
3. C.The set of all x such that x ∈ A and x ∉ B
4. D.The set of all x such that x ∉ A and x ∉ B