Let , , and . Verify that
.
Given A = {1, 2}, B = {1, 2, 3, 4}, C = {5, 6}.
Step 1: Find B ∩ C. B ∩ C = {1, 2, 3, 4} ∩ {5, 6} = φ (empty set, since no common elements)
Step 2: Find A × (B ∩ C). A × (B ∩ C) = A × φ = φ
Step 3: Find A × B. A × B = {(1,1), (1,2), (1,3), (1,4), (2,1), (2,2), (2,3), (2,4)}
Step 4: Find A × C. A × C = {(1,5), (1,6), (2,5), (2,6)}
Step 5: Find (A × B) ∩ (A × C). Since A × B has second elements from {1,2,3,4} and A × C has second elements from {5,6}, there are no common ordered pairs. (A × B) ∩ (A × C) = φ
Conclusion: A × (B ∩ C) = φ = (A × B) ∩ (A × C). Hence verified.
is a subset of .
Given A = {1, 2}, B = {1, 2, 3, 4}, C = {5, 6}, D = {5, 6, 7, 8}.
Step 1: Find A × C. A × C = {(1,5), (1,6), (2,5), (2,6)}
Step 2: Find B × D. B × D = {(1,5), (1,6), (1,7), (1,8), (2,5), (2,6), (2,7), (2,8), (3,5), (3,6), (3,7), (3,8), (4,5), (4,6), (4,7), (4,8)}
Step 3: Check if each element of A × C belongs to B × D.
- (1,5) ∈ B × D (since 1 ∈ B and 5 ∈ D) ✓
- (1,6) ∈ B × D (since 1 ∈ B and 6 ∈ D) ✓
- (2,5) ∈ B × D (since 2 ∈ B and 5 ∈ D) ✓
- (2,6) ∈ B × D (since 2 ∈ B and 6 ∈ D) ✓
Conclusion: Every element of A × C is in B × D. Therefore, A × C ⊆ B × D. Hence verified.
Explanation
This question tests understanding of Cartesian products and set operations. For part (i), the distributive property A × (B ∩ C) = (A × B) ∩ (A × C) is verified by computing both sides. Since B and C have no common elements, B ∩ C = φ, making both sides equal to φ. For part (ii), the subset relation is verified by checking that all first elements of A × C belong to B and all second elements belong to D, which is true since A ⊆ B and C ⊆ D.