Consider a particle which moves in a scalar potential V(r)=Vx(x)+Vy(y)+Vz(z).
(a) Show that the Hamiltonian of this particle can be written as H^=H^x+H^y+H^z, where H^x=px2/(2m)+Vx(x), and so on.
(b) Do H^x, H^y, and H^z form a complete set of commuting operators?