Show that each of these equations satisfies translational invariance
Show that each of these equations satisfies translational invariance, that is, if u(x,t) is a solution, then v(x,t)=u(x −φ,t) is also one.
Show that only the last equation satisfies Galilean invariance, that is, if u(x,t) is a solution, then v(x,t)=u(x −V t,t)−V is also one.