There is a slight error in the formula for pressure. It is dimensionally inconsistent. The argument of cosine can't have any dimension. Moreover, two different dimensioned quantities are being added. The error is probably in placing the brackets.
(a)
Sinusoidal variation. As expected, the average (over time) sound level is constant at a fixed distance from the source.
(b)
Because the magnitude of pressure near the source is infinitely large, I have plotted the pressure for
As expected, the intensity of sound level decreases from the distance at a fixed time.
(c)
where
so that
There no expansion needed actually. Just the fact that
Directions: Please answer the following question in complete sentences. Be sure to label all geometric objects...