I want to solve
$$ \dot{\begin{pmatrix}C_1(t)\\C_2(t)\\C_3(t)\end{pmatrix}} = A\cdot\begin{pmatrix}C_1(t)\\C_2(t)\\C_3(t)\end{pmatrix}+\vec{b}(x) = \begin{pmatrix}0&a&b\\-a&0&c\\-b&-c&0\end{pmatrix}\cdot \begin{pmatrix}C_1(t)\\C_2(t)\\C_3(t)\end{pmatrix} + \begin{pmatrix}0\\V_{21}cos(wt)e^{w_{21}t}\\V_{31}cos(wt)e^{w_{31}t}\end{pmatrix} $$
however $A$ is not diagonalizeable. It has no eigenvectors and eigenvalues. Is there still a way to solve this ?