For each operation ∗ defined below, determine whether ∗ is binary, commutative or associative.
For each operation ∗ defined below, determine whether ∗ is binary, commutative or associative.
  1. On Q, define a ∗ b = ab/2
  2. On Z+, define a ∗ b = 2ab

(iii) On Q, characterize a ∗ b = stomach muscle/2

Stage 1: Check for commutative

Consider ∗ is commutative, then, at that point a ∗ b = b * a

Which implies, abdominal muscle/2 = ba/2 or stomach muscle/2 = abdominal muscle/2 (which is valid)

a ∗ b = b * a for each of the a, b ∈ Q

In this way, ∗ is commutative.

Stage 2: Check for Associative.

Consider ∗ is cooperative, then, at that point (a ∗ b)* c = a * (b * c)

LHS = (a ∗ b) * c = (stomach muscle/2) * c

???????? ×????

= 2

2

= abc/4

RHS = a * (b * c) = a * (bc/2)

????×????????

= 2

2

= abc/4

This infers LHS = RHS

Accordingly, ∗ is acquainted parallel activity.

(iv) On Z+, characterize a ∗ b = 2ab

Stage 1: Check for commutative

Consider ∗ is commutative, then, at that point a ∗ b = b * a

Which implies, 2ab = 2ba

or then again 2ab = 2ab (which is valid)

a ∗ b = b * a for every one of the a, b ∈ Z+ Therefore, ∗ is commutative. Stage 2: Check for Associative.

Consider ∗ is acquainted, then, at that point

(a ∗ b)* c = a * (b * c)

LHS = (a ∗ b) * c = (2ab ) * c

= 22???????? ????

RHS = a * (b * c) = a * 2bc

= 22???????? ????

This infers LHS ≠ RHS

In this way, ∗ isn’t cooperative paired activity.