The function is
.
Find the inverse function.
\Change
to
.
.
Interchange
and
.
.
Add
to each side.
Apply inverse trigonometric property:
.
.
Subtract each side by
.
.
.
The inverse function is
.
Find the range of
:
.
Add
to each side.

Range of the tangent function:
.
Here

.
The range of
is
or
.
The domain of
is range of
.
The range of
is
.
Hence the domain of
is
. \ \
The range of of
is domain of
.
The domain of
is
or
.
Hence the range of
is
.
The inverse function is
.
The range of
is
.
The domain of of
is
.
The range of
is
.