Question

Which of the following relation do not represent a function?

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

A function is said to be function, if each input have only one ouput.

Let's take the first mapping diagram


Pairs (1, 9), (5, 8) and (4, 11) have exactly one input related to one output.
(2, 10) and (3, 10) have two inputs related to one output.
So, it is a function.

Let's take the second mapping diagram


Pairs (1, D), (2, C), (3, E), (4, A) and (5, B) have exactly one input related to one output. So, it is a function.

Let's take the third mappig diagram


Pairs (1, A), (2, A), (3, A), (4, A) and (5, A) have five inputs related to one output. So, it is a function.

Let's take the fourth mapping diagram


(A, 1) (A, 2), (A, 3), (A, 4) and (A, 5) have one input related to five outputs. So, it this is not a function.

∴ Fourth mapping diagram does not represent a function.