Let f = {(3, 1), (9, 3), (12, 4)} and g = {(1, 3), (3, 3), (4, 9), (5, 9)}. Show that gof and fog are both defined, Also, find fog and gof.

Let f = {(3,1), (9,3), (12,4)} and


g = {(1,3), (3,3), (4,9), (5,9)}


Now,


range of f = (1, 3, 4}


domain of f = {3, 9, 12}


range of g = {3,9}


domain of g = (1, 3, 4, 5}


since, range of f domain of g


gof is well defined.


Again, the range of g domain of f


fog in well defined.


Finally, gof = {(3,3), (9 ,3), (12,9)}


fog = {(1,1) , (3,1), (4,3), (5,3)}


2