Why does this
RSolve[{y[t] == a*y[t - 1]}, {y[t]}, t]
work, while this
RSolve[{y[t] == a[t - 1]*y[t - 1], a[t] == a[t - 1]}, {y[t], a[t]}, t]
does not given any interesting result?
My goal is to solve something of the kind:
RSolve[{y[t] == function[y[t - 1],a[t-1]], a[t] == b*a[t - 1]}, {y[t], a[t]}, t]
a[t]is decoupled from the rest, can't you solve it first and then use the solution in the equation fory[t]? – b.gates.you.know.what Apr 10 '14 at 07:08