FILOMAT, cilt.25, sa.3, ss.145-151, 2011 (SCI-Expanded)
Text of the abstract. The main purpose of this paper is to introduce a new instability theorem related to a fifth order nonlinear differential equation with a constant delay. By means of the Lyapunov-Krasovskii ([8], [13]) functional approach, we obtain a new result on the topic.