Consider wave propagation in an aeolotropic medium such as a single crystal where Hooke’s law in its most general form must be employed. (i) Show that in this case there are three distinct velocities...

Consider wave propagation in an aeolotropic medium such as a single crystal where Hooke’s law in its most general form must be employed. (i) Show that in this case there are three distinct velocities of propagation of a plane wave. Also show that the vibration directions accompanying the three velocities are mutually perpendicular. (ii) Explain the consequences of any two of these three velocities being equa