JEE Main20231 Feb 2023Morning ShiftMathematicsSets and RelationsActual
Let R be a relation on ℝ , given by R = a , b : 3 a - 3 b + 7 is an irrational number . Then R is
Options
- AReflexive but neither symmetric nor transitive
- BReflexive and transitive but not symmetric
- CReflexive and symmetric but not transitive
- DAn equivalence relation
Correct answer
A. Reflexive but neither symmetric nor transitive
Step-by-step solution
Given: R = a , b : 3 a - 3 b + 7   is   irrational Reflexive: 3 a - 3 a + 7 = 7 is irrational. So, a , a ∈ R , hence R is reflexive. Given: R = a , b : 3 a - 3 b + 7   is   irrational Symmetric: Let a , b ∈ R , then 3 a - 3 b + 7 is irrational. So, 3 b - 3 a + 7 is not necessarily irrational, since if 3 a = 7 and 3 b ∈ Z , then 3 a - 3 b + 7 is irrational., but 3 b - 3 a + 7 is not irrational. So, a , b ∈ R ⇒ b , a ∈ R , hence R is not symmetric Transitive: Ta