Elephants can create and detect infrasonic sounds sounds with frequencies lower than about $20$ Hz which can travel long distances. They create these sounds using the cavity that extends from their larynx to the tip of their long trunk. Consider this cavity as a cylindrical air column of length $4\mathrm{.}66$ meters that is closed at the larynx and open at the tip of the trunk.Calculate the fundamental frequency of a standing wave in such an elephants air column, in hertz. Take the speed of sound in air to be $351$ m$/$s$.$