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JEE Main20252 Apr 2025Morning ShiftMathematicsSets and RelationsActual

Let A be the set of all functions f: Z Z and R be a relation on A such that R = ( f , g ): f(0)= g (1) and f(1)= g (0) . Then R is:

Options

  1. ASymmetric and transitive but not reflective
  2. BSymmetric but neither reflective nor transitive
  3. CReflexive but neither symmetric nor transitive
  4. DTransitive but neither reflexive nor symmetric

Correct answer

B. Symmetric but neither reflective nor transitive

Step-by-step solution

aligned & R = ( f , g ): f (0)= g (1) and f (1)= g (0) & Reflexive: ( f , f ) R & = f (0)= f (1) and f (1)= f (0) must hold & but this is not true for all function aligned so not reflexive Symmetric: If ( f , g ) R ( g , f ) R Now, g(0)=f(1) and g(1)=f(0) true symmetric Transitive : If ( f , g ) R and ( g , h ) R ( f , h ) R Now (f, g) R f(0)=g(1) and f(1)=g(0) ( g , h ) R g (0)= h (1) and g (1)= h (0) For (f, h) R we need f(0)=h(1) and f(1)=h(0) Now f(0)=g(1)=h(0) and f(1)=g(0)=h(1) Hence not transitive

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