Exercise · ZW-RELATIVE-COMPLEMENT-007 · ★★☆ Intermediate
How many elements does \(\{2,4\} \setminus A\) have, if \(A = \{1,2,3,4\}\)?
Choose one option.
Show answer
- C. \(0\)
Explanation
Both 2 and 4 belong to \(A\), so none falls outside it: the set is empty.
Review the concept: Relative complement
The relative complement of \(B\) in \(A\) is the set \(A \setminus B\) of elements of \(A\) that do not belong to \(B\).
\[A \setminus B = \{x \in A : x \notin B\}\]
More practice problems: relative complement
- ZW-RELATIVE-COMPLEMENT-001 What does x ∈ A setminus B mean?
- ZW-RELATIVE-COMPLEMENT-002 If A = \a,b,c\ and B = \b\, what is A setminus B?
- ZW-RELATIVE-COMPLEMENT-003 What is A setminus A?
- ZW-RELATIVE-COMPLEMENT-004 What relation does A setminus B satisfy with A?
- ZW-RELATIVE-COMPLEMENT-005 Let A = \1,…,10\ and B = \2,4,6,8,10,12\. What is A setminus B?
- ZW-RELATIVE-COMPLEMENT-006 Which statement is true for any sets A and B?
- ZW-RELATIVE-COMPLEMENT-008 If A setminus B = ∅, what can be concluded?
- ZW-RELATIVE-COMPLEMENT-009 Let A = \1,…,20\, B_1 = A setminus \x : x is even\ and B_2 = A setminus B_1. What is B_2?