Abstract:
In this thesis we studied systems of differential equations .Chapter one deal with systems of differential equations of first order by different methods, also we studied the existence and uniqueness of the solutions.
In chapter two we studies solutions of homogeneous and nonhomogeneous linear systems of differential equations (first order) using different methods.
In chapter three deals with Lyapunov stability theory we studied Lyapunov stability and stability in the first approximation.
