[" 1) Give an example to show that "*:NXN rarr" N given by "*(a,b)=a-b" is not a binary of "],[" 2) Write the domain of "f(x)=sec^(-1)x],[" 3) Find the number of all possible matrices of order "3times3" with each entry "0" or "1" ."],[" What is concediaint of a matrive matrices of order "3times3" with each entry "0" or "1" ."]