# Which of the following relations are functions? Give reasons. If it is a function, determine its domain and range

(i) {(2,1), (5,1), (8,1), (11,1), (14,1), (17,1)}

(ii) {(2,1), (4,2), (6,3), (8,4), (10,5), (12,6), (14,7)}

(iii) {(1,3), (1,5), (2,5)}

**Solution:**

**(i)** {(2, 1), (5, 1), (8, 1), (11, 1), (14, 1), (17, 1)}

Since 2, 5, 8, 11, 14, and 17 are the elements of the domain of the given relation having their unique images, this relation is a function.

Here, domain = {2, 5, 8, 11, 14, 17} and range = {1}

**(ii)** {(2, 1), (4, 2), (6, 3), (8, 4), (10, 5), (12, 6), (14, 7)}

Since 2, 4, 6, 8, 10, 12 and 14 are the elements of the domain of the given relation having their unique images, this relation is a function.

Here, domain = {2, 4, 6, 8, 10, 12, 14} and

range = {1, 2, 3, 4, 5, 6, 7}

**(iii)** {(1, 3), (1, 5), (2, 5)}

Since the same first element that is, 1 corresponds to two different images that are, 3 and 5, this relation is not a function

NCERT Solutions Class 11 Maths Chapter 2 Exercise 2.3 Question 1

## Which of the following relations are functions? Give reasons. If it is a function, determine its domain and range. (i) {(2,1), (5,1), (8,1), (11,1), (14,1), (17,1)} (ii) {(2,1), (4,2), (6,3), (8,4), (10,5), (12,6), (14,7)} (iii) {(1,3), (1,5), (2,5)}

**Summary:**

Three relations are given. We have found that the first two relations are functions but the third one is not a function