There are solutions of (32.2.1) such that

where
and
and
are constants.
There are also solutions of (32.2.1) such that
Next, for given initial conditions
and
, with
real,
has at least one pole on the real axis. There are two special values of
,
and
, with the properties
,
, and such that:
If
, then
for
, where
is the first
pole on the negative real axis.
If
, then
oscillates about, and is asymptotic to,
as
.
If
, then
changes sign once, from positive to negative,
as
passes from
to 0.
Consider the special case of
with
:
with boundary condition
Any nontrivial real solution of (32.11.4) that satisfies
(32.11.5) is asymptotic to
, for some nonzero
real
, where
denotes the Airy function (§9.2).
Conversely, for any nonzero real
, there is a unique solution
of (32.11.4) that is asymptotic to
as
.
If
, then
exists for all sufficiently large
as
, and
where
and ![]()
,
are real constants. Connection formulas for
and
are given by
where
is the gamma function (§5.2(i)), and the
branch of the
function is immaterial.
If
, then

If
, then
has a pole at a finite point
, dependent
on
, and

Replacement of
by
in (32.11.4) gives
Any nontrivial real solution of (32.11.12) satisfies

where
with ![]()
and
arbitrary real constants.
In the case when
with
, we have

where
is a nonzero real constant. The connection formulas for
are

In the generic case
we have

where
, ![]()
, and
are real constants, and
The connection formulas for
,
, and
are
where
For
, with ![]()
and
,

where
is an arbitrary constant such that
,
and
where
and
are arbitrary constants such that
and
. The connection formulas relating
(32.11.25) and (32.11.26) are
Consider
with ![]()
and
, that
is,
and with boundary condition
Any nontrivial solution of (32.11.29) that satisfies
(32.11.30) is asymptotic to
as
, where ![]()
is a constant. Conversely, for any ![]()
there is a unique
solution
of (32.11.29) that is asymptotic to
as
. Here
denotes the parabolic cylinder function (§12.2).
Now suppose
. If
, where
then
has no poles on the real axis. Furthermore, if
, then

Alternatively, if
is not zero or a positive integer, then

where
and ![]()
and
are real constants. Connection formulas for
and
are given by
where
and the branch of the
function is immaterial.
Next if
, then
and
has no poles on the real axis.
Lastly if
, then
has a simple pole on the real axis, whose
location is dependent on
.
For illustration see Figures 32.3.7–32.3.10. In terms of the parameter
that is used in these figures
.
See also Wong and Zhang (2009a).