Question

Let X = {3, 4, 6, 8}. Determine whether the relation 

R = {(x, f(x)) |x ∈ X, f(x) = x² + 1} is a function from X to N?

Answer 1

f(x) = x² + 1 

f(3) = 3² + 1 = 9 + 1 = 10

f(4) = 4² + 1 = 16 + 1 = 17 

f(6) = 6² + 1 = 36 + 1 = 37 

f(8) = 8² + 1 = 64 + 1 = 65 

Yes, R is a function from X to N