Oscillation Properties of the Equation of Boussinesq and Comparison with Other Fourth Order Equations

摘要

In this paper we establish sufficient conditions for the absence of eventually positive solutions of Boussinesq equation: z~(iv)(t)+ z(t)+z~2(t)+ z(t)=F(t)_1 where and are proper constants as well as F(t) C([T,); R), T 0 is a large enough constant. Further, we find sufficient conditions for oscillation of the equations z~(iv)(t)+ z(t)+z(t)|z(t)|+ z(t)=F(t) and z~(iv)(t)+ z(t)+z~(2?+1)(t)+ z(t)=F(t)_1 ?N.