The domain of g alone is {x | x ≠ 0}, and the domain of f is all reals. So the domain of (f ◦ g) is the domain of g
{x | x ≠ 0}.
(f ◦ g)(x) = 1/x + 3.
The range of g(x) = 1/x is actually the same as its domain {y | y ≠ 0}. Adding three, the range of f ◦ g is all reals except for 3,
{y | y ≠ 3}
The line y = 3 is actually an asymptote (horizontal) to the graph of f ◦ g.
