Abstract
We consider the structure of positive radial solutions of
Δ
u
+
u
−
α
−
u
−
β
=
0
in
B
R
,
u
=
0
on
∂
B
R
,
where
B
R
is a ball in
R
N
with radius
R. When
0
<
α
<
β
<
1
, we show that there exists
R
∗
>
0
such that when
R
>
R
∗
, the Dirichlet problem has exactly two radial solutions; when
R
=
R
∗
, the solution is unique and there is no solution for
R
<
R
∗
. When
0
<
β
<
α
<
1
, we show that for any
R
>
0
, the radial solution exists and is unique.