the problems is that: two loudspeakers, A and B, radiate sound uniformly in all directions in air at 20 degree C. The acoustic power output from A is 8x10^-4 W, and from B it is 6x10^-5 W. Both loudspeakers are vibrating in phase at a frequency of 172 Hz. a) Determine the difference in phase of the two signals at a point C along the line joining A and B, 3m from B and 4m from A. b) Determine the intensity and sound intensity level at C from speaker A if speaker B is turned off and the intensity and sound intensity level at point C from speaker B if speaker A is turned off. c) With both speakers on, what are the intensity and sound intensity level at C? In part a, i have tried to work out the y(x,t)=Acos(kx-wt) of both loudspeakers, then add them together, I have got the result 2A, but their phase difference is pi (3.14). In part b, i have no idea how to link the power and intensity together. thanks for attention.