1.

For any two real number a b and , we defined aRb if and only if sin2a + cos2b = 1. The relation R is(a) reflexive but not symmetric (b) symmetric but not transitive (c) transitive but not reflexive (d) an equivalence relation

Answer»

(d) an equivalence relation

Given, a R b ⇒ sin2a + cos2b = 1 

Reflexive: a R a ⇒ sin2 a + cos2 a = 1 ∀ a ∈ R (True) 

Symmetric: a R b ⇒ sin2 a + cos2 b = 1 

⇒ 1 – cos2 a + 1 – sin2 b = 1 

⇒ sin2 b + cos2 a = 1 

⇒ b R a ∀ a, b ∈ R (True) 

Transitive: a R a and b R c 

⇒ sin2 a + cos2 b = 1 and sin2 b + cos2 c = 1 

∴ Adding these two equations we get 

sin2 a + cos2 b + sin2 b + cos2 c = 2 

⇒ sin2 a + cos2 c = 1 ⇒ a R c (True)

R is an equivalence relation.



Discussion

No Comment Found

Related InterviewSolutions