Question:
Let f and g be two functions given by
f = {(2, 4), (5, 6), (8, −1), (10, −3)} and g = {(2, 5), (7, 1), (8, 4), (10, 13), (11, −5)}.
Find the domain of f + g.
Solution:
It is given that f and g are two functions such that
f = {(2, 4), (5, 6), (8, −1), (10, −3)}
and g = {(2, 5), (7, 1), (8, 4), (10, 13), (11, −5)}
Now,
Domain of f = Df = {2, 5, 8, 10}
Domain of g = Dg = {2, 7, 8, 10, 11}
∴ Domain of f + g = Df ∩ Dg = {2, 8, 10}