Let ∗ be a binary operation on the set Q of rational numbers as follows:
a ∗ b =
Find which of the binary operations are commutative and which are associative.
It is given that ∗ be a binary operation on the set Q of rational numbers is defined as
a ∗ b =
For a, b ϵ Q, we get,
a * b = = b * a
⇒ the operation is commutative.
For a, b, c ϵ Q, we get,
(a * b) * c =
a * (b * c) = a *
⇒ (a * b) * c = a * (b * c)
Therefore, the operation * is associative.