In Fig. 1, two speakers separated by distance d1  2.00 m are in phase. Assume the amplitudes of the sound waves from the speakers are approximately the same at the listener’s ear at distance d2  3.75 m directly in front of one speaker. Consider the full audible range for normal hearing, 20 Hz to 20 kHz. (a) What is the lowest frequency fmin,1 that gives minimum signal (destructive interference) at the listener’s ear? By what number must fmin,1 be multiplied to get (b) the second lowest frequency fmin,2 that gives minimum signal and (c) the third lowest frequency fmin,3 that gives minimum signal? (d) What is the lowest frequency fmax,1 that gives maximum signal (constructive interference) at the listener’s ear? By what number must fmax,1 be multiplied to get (e) the second lowest frequency fmax,2 that gives maximum signal and (f) the third lowest frequency fmax,3 that gives maximum signal?