Which one of the following relations on R is an equivalence relation?
aR1b⇔|a|=|b|
aR2b⇔a≥b
aR3b⇔a divides b
aR4b⇔a<b
aR1b⇔|a|=|b| satisfies.
Inequality operation can't be reflective, symmetric
so it is not equivalence
but equality is reflexive, symmetric, and transitive
so this relation is equivalence