1. The problem statement, all variables and given/known data Two identical speakers, 10.0 m apart from each other, are stimulated by the same oscillator, with a frequency f, of 21.5 Hz, at a place where the speed of sound is 344 m/s. a) Show that a receiver at A will receive the minimum intensity of sound (Amin) due to the inerference of the waves produced by the two speakers. b) Show that in order for the sound intensity to remain the same, the receiver, being at the same level as the speakers, has to follow the hyperbolic: 9x2 -16y2 = 144 c) Can the receiver distance itself from the speakers and still keep receiving the minimum sound intensity? If yes, write down the route it must take. If not, write down how far it can go. PS: I wrote down the right speaker as (1), and the left speaker as (2). 2. Relevant equations Δr = | r2 - r1 | v = λf 3. The attempt at a solution a) v = λf <=> λ = 344 m/s / 21.5 Hz = 16.0 m r1 = (10.0 - 9.00) m = 1.00 m r2 = 9.00 m Δr = |9.00 - 1.00|m = 8.00 m = 16.0/2 m = λ/2 = 1*λ/2 = n*λ/2, with n = 1 Therefore, the two waves have a phase difference of π rads or 180 degrees, and cancel each other out. So the receiver... receives, sound with the minimum intensity (0). b) And this is where I get stuck. I looked around for some examples, but no luck. The basic principle is essentially that Δr must always result in n*λ/2. I did create an imaginary triangle at the (x,y) point, so that I can have new versions of r1 & r2, but I can't figure out how to connect them with x & y and end up with the hyperbolic. Any help is appreciated!