Springer Iranian Journal of Science 2731-8095 29 3 2005 02 27 INSTABILITY OF SOLUTIONS OF CERTAIN NONLINEAR VECTOR DIFFERENTIAL EQUATIONS OF ORDER SEVEN 515 521 2825 10.22099/ijsts.2005.2825 EN C. TUNC 1Department of Mathematics, Faculty of Sciences and Literature, Yüzüncü Yil University, 65080, Van, Turkey E. TUNC Department of Mathematics, Faculty of Science and Literature, Gaziosman Paşa University, 60080, Tokat, Turkey Journal Article 2004 06 22 Sufficient conditions are established under which the zero solution X = 0 of equation (2) is<br />unstable. Nonlinear differential equations seventh order instability Lyapunov’s second (direct) method https://ijsts.shirazu.ac.ir/article_2825_a8ec38612da6961acdeef265e22fd009.pdf