Electronic Journal of Differential Equations,
Vol. 2006(2006), No. 109, pp. 1-10.

Title: Instability results for certain third order nonlinear 
       vector differential equations

Authors: Cemil Tunc (Yuzuncu Yil Univ., Van, Turkey)
         Ercan Tunc (Gaziosmanpasa Univ., Tokat, Turkey)
	 
Abstract: 
 Our goal in this paper is to obtain  sufficient conditions
 for instability of the zero solution to the non-linear
 vector differential equation
 $$
 \dddot{X}+F(X,\dot{X})\ddot{X}+G(\dot{X})+H(X)=0.
 $$
 An example illustrates the results obtained.

Submitted July 5, 2006. Published September 11, 2006.
Math Subject Classifications: 34D05, 34D20.
Key Words: Instability, Lyapunov's second (or direct) method; 
           nonlinear differential equations of third order.