Let S be a relation on the set R of all real numbers defined by S = {(a, b) ∈ R × R : a2 + b2 = 1}. Prove that S is not an equivalence relation on R.
S = {(a, b) : a2 + b2 =1}
Proof :
To prove that relation is not equivalence, we need to prove that it is either not reflexive, or not symmetric or not transitive.
Reflexivity : For Reflexivity, we need to prove that-
(a, a) ∈ R
Let a = 1/2, a ∈ R
Then,
⇒ (a, a) ∉ S
⇒ S is not reflexive
Hence, S is not an equivalence relation on R.