JEE Main202127 Jul 2021Evening ShiftMathematicsSets and RelationsActual
Let N be the set of natural numbers and a relation R on N be defined by R = x , y ∈ N × N : x 3 - 3 x 2 y - x y 2 + 3 y 3 = 0 . Then the relation R is
Options
- Asymmetric but neither reflexive nor transitive
- Breflexive but neither symmetric nor transitive
- Creflexive and symmetric, but not transitive
- Dan equivalence relation
Correct answer
B. reflexive but neither symmetric nor transitive
Step-by-step solution
x 3 - 3 x 2 y - x y 2 + 3 y 3 = 0 ⇒ x x 2 - y 2 - 3 y x 2 - y 2 = 0 ⇒ x - 3 y x - y x + y = 0 Now, x = y   ∀ x , y ∈ N × N so its a reflexive relation. But not symmetric & transitive Since, 3 , 1 satisfies but 1 , 3 does not. Also 3 , 1 & 1 , - 1 satisfies but 3 , - 1 does not.