Properties of Union Sets –
Let, A, B, C be any sets, then
(1) A ∪ B = B ∪ A (Commutative Law)
(2) (A ∪ B) ∪ C = A ∪ (B ∪ C) (Associative Law)
(3) A ⊆ A ∪ B and B ⊆ A ∪ B
(4) If A ⊆ B, then A ∪ B = B
(5) A ∪ ϕ = A
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