Let ∗ be the binary operation on N
given by a∗b=L.C.M. of a and b. Find
(i) 5∗7 , 20∗16 (ii) is ∗ communitative?
(iii) is ∗ associative?
(iv)Find the identity of ∗ in N
(v) which elements of N are invertible
for the operation ∗?
Let ∗′ be the binary operation on the set {1,2,3,4,5} defined by a∗′b=H.C.Fof a and b.
Is the operation ∗′ same as the operation ∗ defined above? justify your answer.