Equivalence Relation/Examples/Equal Sine of pi x over 6 on Integers/Proof 2

Proof
We have that $\RR \subseteq \R \times \R$ is the relation induced by $\sin \dfrac {x \pi} 6$:
 * $\tuple {x, y} \in \RR \iff \sin \dfrac {x \pi} 6 = \sin \dfrac {y \pi} 6$

The result follows from Relation Induced by Mapping is Equivalence Relation.