Relation: Let O and P are two Sets then relation 'R' defined from set 'O' to set 'P', is a subset of O * P. Relation is denoted in list form and in tabular form as well.

Let's discuss how to determine if a relation is a function. We will understand it with help of an example in step form:

**Step 1:**Suppose we have Relations:

(4, 5), (6, 10), (10, 10), (3, 4)

(0, 0), (0, 1), (1, 4), (2, 4)

(3, 2), (5, 6), (9, 5), (2, 0)

(9, 4), (9, 0), (8, 8), (5, 8)

Here we have to determine whether each relation is a function not.

**Step 2:**Here we will see case for each relation one by one. Function is a relation if, no two ordered pair have same first value.

So in first case: (4, 5), (6, 10), (10, 10), (3, 4).

This relation is a funciton because none of the four ordered pairs have same first element.

In case of second relation: (0, 0), (0, 1), (1, 4), (2, 4).

Given relation is not a function because first two ordered pair have same first element.

In case of third relation: (3, 2), (5, 6), (9, 5), (2, 0).

In this case given relation is a function because none of the first element in four ordered pair is same.

In last relation (9, 4), (9, 0), (8, 8), (5, 8).

It is not a function because first two ordered pair have first same element.

In this way we can determine relation is a function or not.