JEE Mains · Maths · STD 12 - 1. relation and function
Let \(A=\{-4,-3,-2,0,1,3,4\}\) and \(R =\{( a , b ) \in A\) \(\times A : b =| a |\) or \(\left.b ^2= a +1\right\}\) 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 \(........\).
- A \(5\)
- B \(7\)
- C \(6\)
- D \(4\)
Answer & Solution
Correct Answer
(B) \(7\)
Step-by-step Solution
Detailed explanation
\(R=[(-4,4),(-3,3),(3,-2),(0,1),(0,0),(1,1)\), \((4,4),(3,3)\}\) For reflexive, add \(\Rightarrow(-2,-2),(-4,-4),(-3,-3)\) For symmetric, add \(\Rightarrow(4,-4),(3,-3),(-2,3),(1,0)\)
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