A For steady input K, the compartment moves from initial size q to final size 2 Compartments: I1 1 12 dq 1 - _(f , + f, )9, + $ 1292 + 1, (t) (6) 42 dt 41 a92 = f q - (f + f, )q, + 1, (t ) (7) dt Simple case: system is closed dq, - - f 9, + $ 1292 dt da 2 = f 9, - $1292 dt