5. (Ch. 14 - Problem 81 in Wolfson) Two loudspeakers are mounted 2.85 m apart,
pointing in the same direction and producing identical sound waves of a fixed fre-
quency. You're standing 10.0 m from the speakers, on the perpendicular bisector of
the line between them. You move in direction parallel to the line between the speak-
ers and find that the sound intensity diminishes, reaching a minimum when you've
moved 2.44 m. If the sound speed is 343 m/s, what is the frequency of the sound
waves?