Positive radial solutions for quasilinear biharmonic equations

We study the quasilinear biharmonic problem {Δ(|Δu|p−2Δu)=f(|x|,u)+g(|x|),x∈B1,u=Δu=0,x∈∂B1, where B1={x∈RN:|x|<1} with N≥2. Criteria are established for the existence of at least one positive radial solution of the problem. Explicit lower and upper bounds of the solutions are obtained in our results.