3  Types of Functions
The notion of a function along with some special functions like identity function, constant
function, polynomial function, rational function, modulus function, signum function etc along with their graphs have been given in Class XI Addition, subtraction, multiplication and division of two functions have also been
studied As the concept of function is of paramount importance in mathematics and
among other  disciplines as well, we would like to extend our study about function from
where we finished earlier