Two speakers emitting identical 236 Hz tones are placed on a line a distance LaTeX: \Delta x away from each other and po

[answerhappygod]

Two speakers emitting identical 236 Hz tones are placed on a
line a distance LaTeX: \Delta x away from each other and pointed in
the same direction. As you walk along this line away from the pair
of speakers (both are behind you and pointed in your direction),
you don't hear anything even though the speakers are both producing
sound. This is true no matter how far away you are from the nearest
speaker. After some experimentation, you find that there are
multiple separations between the pair of speakers, Delta x, that
give rise to this same phenomena where no sound is heard along the
line despite the fact that both speakers are working. What is the
second smallest value of Delta x? To be clear, I'm not asking for
the smallest value—I'd like to know what the next smallest value is
after that smallest value. Assume that the speed of sound for the
temperature of the air surrounding the speakers is 331 m/s.