Which of the following relations are functions Solutiona is

Which of the following relations are functions?

Solution

(a) is not a function as it as 2 different output values for the same input . for e.g. when x=0 , why is taking both positive and negative values for the same input. As per function definition , every input can have only one output

(b) is a function. It is an example of f(x)=IxI

(c) Is not a function as it as 2 different output values for the same input

(d)Is a function. It is an example of f(x)=x