Question

Let f and g be two functions given by

f = {(2, 4), (5, 6), (8, – 1), (10, – 3)} g = {(2, 5), (7, 1), (8, 4), (10, 13), (11, – 5)} then. Domain of f + g is __________

Answer 1

Since Domain of f = D_f = {2, 5, 8, 10} and Domain of g = D_g = {2, 7, 8, 10, 11}, 

therefore the domain of f + g = {x | x ∈ D_f ∩ D_g} = {2, 8, 10}