Briefly given a function f(x), the domain is the set of values x may have. If we have the graph of f(x) we may be able to read the domain off the x – axis. The graph below is y=ln(x). The domain is obviously, from the x – axis, x>0. It is much harder to see that the range, the set of values y may have, is the set of real numbers, also written
or 
The endpoints
are not included.
The graph above is
Unless we restrict the domain in some way, for example,
, then the domain isand the range we can read off the y axis: [-3,3]. The square brackets indicate the endpoints are included in the range.
To find the graph of the inverse of a function we reflect the graph of the function in the line
This is shown above. The red curve is the curve
The inverse to
is the curve
shown in blue.