Determine which of the following binary operations on the set $N$ are associative and which are commutative: $a \ast b = 1$ for all $a, b \in N$.

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(A) $1$. Commutativity: $A$ binary operation $\ast$ on a set $N$ is commutative if $a \ast b = b \ast a$ for all $a, b \in N$. Here,$a \ast b = 1$ and $b \ast a = 1$. Since $1 = 1$,the operation is commutative.
$2$. Associativity: $A$ binary operation $\ast$ on a set $N$ is associative if $(a \ast b) \ast c = a \ast (b \ast c)$ for all $a, b, c \in N$. Here,$(a \ast b) \ast c = 1 \ast c = 1$. Also,$a \ast (b \ast c) = a \ast 1 = 1$. Since $1 = 1$,the operation is associative.
Therefore,the operation is both associative and commutative.

Explore More

Similar Questions

Show that addition, subtraction, and multiplication are binary operations on $R$, but division is not a binary operation on $R$. Further, show that division is a binary operation on the set $R_*$ of nonzero real numbers.

The set $\{-1, 0, 1\}$ is not a multiplicative group because of the failure of

Consider a binary operation $*$ on $N$ defined as $a * b = a^{3} + b^{3}$. Choose the correct answer.

Show that subtraction and division are not binary operations on the set of natural numbers $N$.

If $*$ is a binary operation defined on $R$ by $a * b = 1 + ab, \forall a, b \in R$. Then the operation $*$ is:

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo