Hw6 ex3.b - choice of times
In this problem, you can pick arbitrary times for the intermdiate and final position of the vehicle, e.g. t=0, t=1, t=2.
You need these times in order to solve the linear equations to find the parameters of the approximating functions of the flat output you chose.
If the chosen basis functions for the approximation are monimials, there is no other degree of freedom for this problem.