BITSAT2017MathematicsSets and RelationsActual
Let A = 1 , 2 , 3 , 4 , 5 and R be a relation defined by R = ( x , y ) : x , y ∈ A , x + y = 5 . Then, R is
Options
- Areflexive and symmetric but not transitive
- Ban equivalence relation
- Cneither reflexive nor transitive
- Dneither reflexive nor symmetric but transitive
Correct answer
C. neither reflexive nor transitive
Step-by-step solution
We first write the elements of the set R . i.e. R = ( 1 , 4 ) , ( 4 , 1 ) , ( 2 , 3 ) , ( 3 , 2 ) Since, ( 1 , 1 ) ∉ R ⇒ R is not reflexive. Now as, ( 1 , 4 ) ∈ R ⇒ ( 4 , 1 ) ∈ R and ( 2 , 3 ) ∈ R ⇒   ( 3 , 2 ) ∈ R So, R is symmetric Now, ( 1 , 4 ) ∈ R and ( 4 , 1 ) ∈ R Thus, R is not transitive. Hence, R is symmetric but neither reflexive nor transitive.