Consider sounds created by (a) a flute continuously sounding a steady note, (b) struck xylophone bar, (c) a steadily bowed violin, (d) a snare drum, (e) a steadily blown oboe, and (f) a struck piano string. In view of the rules in Section 8.2, in which three cases is the vibration recipe required to be precisely a harmonic series? In which three is it permitted to be nonharmonic? In which of those last three is it nevertheless probably quite close to harmonic, and why do you think so