You are given the discrete-time dynamical system l_{t+1} = l_t - 1.7 with initial conditions l_0 = 13.1cm. Calculate the states of the system for the next five steps, i.e find l_1, l_2, ..., l_5:
Now find the solution of this system, i.e. length l(t) as a function of time t.
Now use this function to evaluate the length at t = 20: