Given for the problem:(adsbygoogle = window.adsbygoogle || []).push({});

A speaker sends out two sound waves with equal Amplitudes but the frequencies are f(1) and f(2) respectively. The motion of sound as w = A * cos(k*x - t*(Omega)). The wave number's and the angular frequency's definition are the same for light.

Find for the problem:

Show that at a distance x directly in front of the speaker, there is destructive interference between the waves with a frequency f(1) - f(2).

My solution so far:

w(1) = A * cos((2PI/(Lambda(1))) * x - (2PI * f(1) * t)

w(2) = A * cos((2PI/(Lambda(2))) * x - (2PI * f(2) * t)

I assume that the final equation will be in the form of:

dt = (x / v) - t

where v is the speed of sound

A little advice please!

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# Homework Help: Sound interference

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