Question

Let N be the set of natural numbers and the relation R be defined on N such that R = {(x,y):y = 2x,x,y ∈ N} What is the domain, co-domain and range of R? Is this relation a function?

Answer 1

Given R = {x, y): y = 2x; x, y ∈ N}

Domain of R = set of natural numbers Co-domain of 

R = set of natural number Range of 

R = set of even natural numbers 

Clearly, every natural number is related to unique image, so this relation is a function.