How to make simple iteration in Mathematica for this three equations and save $q$ for each step. If we define $q'=dq/dx$, $q''=dq'/dx$ we have two equations
(1) $q''[j+1]=a_1(q[j+1]-q[j])-a_3q'[j]-a_5q''[j]$,
(2) $q'[j+1]=a_2(q[j+1]-q[j])+a_4q'[j]+a_6q''[j]$,
And we should substitute in third
(3) $q[j+1]=Q_2q[j]+Q_3q'[j]+Q_4q''[j]$
$a_i$ and $Q_k$ ($i=1,\ldots,6$; $k=1,2,3$) are functions of $\delta(x)$. Where $\delta(x)=0.01$ for example. For each $\delta(x)$ I need $q$.
Regards,