Let B-1(0) subset of IR4 be the unit ball. In this article, we study the existence of multiple positive solutions u is an element of H-0(2)(B-1) of the following biharmonic problem: (P lambda) {Delta 2u = h(u)/vertical bar x vertical bar(beta)e(u alpha) + lambda u(q), u>0 in B-1, u = partial derivative u/partial derivative n = 0 on partial derivative B-1, where 0 < q < 1 < alpha <= 2, lambda is
... [Show full abstract] an element of IR, 0 < beta < 4 and h satisfies certain growth conditions mentioned in Section 1. We show that there exists 0 < Lambda < infinity such that the above problem admits at least two solutions in H-0(2) (B-1) if lambda is an element of ( 0, Lambda), no solution if lambda > Lambda and at least one solution when lambda = Lambda.