Suppose I apply a pair of equal and opposite harmonically varying forces perpendicular to an infinite drum membrane. Consider the following forcing functions at two nearby points,(x=0,y=a) and (x=0,y=-a), separated by a distance 2a,
F(t,0,a) = Acos(ωt), F(t,0,-a) = -Acos(ωt)
Let the forcing...