Please cite this article in press as: R. Dhanya et al., Existence of positive radial solutions for superlinear, semipositone problems on the exterior of a ball, J. Math. Anal. Appl. (2015), http://dx.
AbstractWe study positive radial solutions tois a class of non-decreasing functions satisfying lim s→∞ f (s) s = ∞ (superlinear) and f (0) < 0 (semipositone). We consider solutions, u, such that u → 0 as |x| → ∞, and which also satisfy the nonlinear boundary conditon ∂u ∂η +c(u)u = 0 when |x| = r 0 , where ∂ ∂η is the outward normal derivative, andc ∈ C ([0, ∞), (0, ∞)). We will establish the existence of a positive radial solution for small values of the parameter λ. We also establish a similar result for the case when u satisfies the Dirichlet boundary conditon (u = 0) for |x| = r 0 . We establish our results via variational methods, namely using the Mountain Pass Lemma.