Asymptotics of the eigenvalues of a self-adjoint fourth order boundary value problem with four eigenvalue parameter dependent boundary conditions

Considered is a regular fourth order ordinary differential equation which depends quadratically on the eigenvalue parameter and which has separable boundary conditions depending linearly on . it is shown that the eigenvalues lie in the closed upper half plane or on the imaginary axis and are symmetric with respect to the imaginary axis. the first four terms in the asymptotic expansion of the eigenvalues are provided. © 2013 manfred möller and bertin zinsou.