Determine whether each of the following operations define a binary operation on the given set or not:
‘O’ on Z defined by a O b = ab for all a,b Z.
Given that ‘Ο’ is an operation that is valid in the Integers ‘Z’ and it is defined as given:
⇒ aΟb = ab, where a,b∈Z
Since a∈Z and b∈Z,
According to the problem it is given that on applying the operation ‘*’ for two given integers it gives Integers as a result of the operation,
⇒ aΟb∈Z ...... (1)
Let us values of a = 2 and b = – 2 on substituting in the R.H.S side we get,
⇒ ab = 2 – 2
⇒
⇒ ab∉Z ...... (2)
From (2), we can see that ab doesn’t give only Integers as a result. So, this cannot be stated as a binary function.
∴ The operation ‘Ο’ does not define a binary function on Z.