Question

Let A= {–4, –3, –2, 0, 1, 3, 4} and R = {(a, b) ∈ A × A : b = |a| or b² = a + 1} be a relation on A. Then the minimum number of elements, that must be added to the relation R so that it becomes reflexive and symmetric, is_____.

Answer 1

Correct answer is 7

R = [(–4, 4), (–3, 3), (3, –2), (0, 1), (0, 0), (1, 1), (4, 4), (3, 3)} 

For reflexive, add ⇒ (–2, –2), (–4, –4), (–3, –3) 

For symmetric, add ⇒ (4, –4), (3, –3), (–2, 3), (1, 0)