We continue to consider explicit linear differential equation systems of first order, \(\displaystyle \begin{aligned} \dot{\boldsymbol{x}}(t) = A(t) \, \boldsymbol{x}(t) + \boldsymbol{s}(t) \, , \end{aligned}\) where in this second chapter on this topic we still consider a constant, but not necessarily diagonalisable matrix \(A \in {\mathbb R}^{n \times n}\) and again set \(\boldsymbol {s} = \boldsymbol {0}\) .