A RESULT ON THE INSTABILITY OF SOLUTIONS OF CERTAIN NON-AUTONOMOUS VECTOR DIFFERENTIAL EQUATIONS OF FOURTH ORDER*

Abstract

The main purpose of this paper is to obtain sufficient conditions under which the trivial solution of the vector differential equations of the form
X(4) + A
... X +B(t)H(X,
. X,
.. X,
... X)
.. X +C(t)G(X)
. X +D(t)F(X)=0
is unstable.