Abstract:
The paper is concerned with an ordinary differential equation of the form
\begin{equation}
-\psi''(x)+\biggl(1+\frac c{x^2}\biggr)\psi(x)= \frac1{x^\alpha}|\psi(x)|^{k-1}\psi(x),
\qquad x>0,
\tag{1}
\end{equation}
where $k$ and $\alpha$ are positive parameters, $k>1$, and $c$ is a constant,
subject to the boundary condition
\begin{equation}
\psi(0)=0, \qquad \psi(+\infty)=0.
\tag{2}
\end{equation}
A variational approach based on finding the eigenvalues of the gradient of the functional
$F_{k,\alpha}(f)=\displaystyle\int_0^{+\infty}|f(s)|^{k+1}s^{-\alpha}\,ds$
acting on the space of absolutely continuous functions $H_0^1=\{f:f,f'\in L_2(0,+\infty), f(0)=0\}$ is used to show that if $c>-1/4$, $k>1$, $0<2\alpha<k+3$, then problem
$(1)$, $(2)$ has a countable number of nonzero solutions, at least one of which is positive. For nonzero solutions, asymptotic formulae as $x\to0$ and $x\to+\infty$ are obtained.
Bibliography: 7 titles.
Keywords:differential equation, function space, weakly continuous functional, eigenfunction of the gradient of a functional.