Question

Let A={1,2,3,4,5} and R be a relation from A to A, R = {(x, y): y = x + 1}. Find the domain.

(a) {1,2,3,4,5}

(b) {2,3,4,5}

(c) {1,2,3,4}

(d) {1,2,3,4,5,6}

The question was asked in an international level competition.

My enquiry is from Relations in division Relations and Functions of Mathematics – Class 11

Answer 1

Right answer is (a) {1,2,3,4,5}

For explanation I would say: We know, domain of a relation is the set from which relation is defined i.e. set A.

So, domain = {1,2,3,4,5}.