APPLIED MATHEMATICS & INFORMATION SCIENCES, cilt.8, sa.1, ss.393-399, 2014 (SCI-Expanded)
Kroopnick (2010) discussed the bounded solutions of certain non-autonomous differential equations of the second order by using the integral test. In this paper, instead of the integral test, we study the results of Kroopnick [9] by using the Liapunov's function approach. We compare the established results with that of Kroopnick [9]. We also give some additional results on the equi-bounded solutions and uniformly-bounded solutions, and an example is given for the illustrations.