5
Example 15 Let f : {2, 3, 4, 5} → {3, 4, 5, 9} and g : {3, 4, 5, 9} → {7, 11, 15} be
functions defined as f (2) = 3, f(3) = 4, f(4) =  f(5) = 5 and g (3) = g (4) = 7 and
g (5) =  g(9) = 11 Find gof Solution We have gof (2) =  g (f (2)) = g (3) = 7, gof (3) =  g (f (3)) = g (4) = 7,
gof(4) =  g (f(4)) = g (5) = 11 and gof(5) =  g (5) = 11 Example 16 Find gof and fog, if f : R → R and g : R → R are given by f(x) = cos x
and g(x) = 3x2