# Functions-12

### From Homeworkwiki

**Let f be a relation on the set N of natural numbers defined by f = {(n, 3n) n ∈ N}.**

**Is f a function from N to N. If so, find the range of f.**

**Solution:** Since for each n ∈ N, there exists a unique 3n ∈ N such that (n, 3n) ∈ f. Therefore, f is a function
from N to N,

Now, Range of f = {f(n) : n ∈ N} = {3n : n ∈ N}.