Rewrite system as a single equation in n, by assuming that n3 = 0 and subtracting the remaining equations to get an equation for n′ = (n2 − n1)′.

n′ =(W+G)n

where W= \begin{bmatrix} -Wp&0&Wp\\ 0& 0& 0\\ Wp& 0 & -Wp \end{bmatrix} and G=\begin{bmatrix} 0 &r21 &r31 \\ 0&-r21&r32 \\ 0&0 &-r32-r31 \end{bmatrix}