Chapter 5, Problem 5.5P

Consider the following time-varying current density, which is in the form of a propagating wave at frequency f, traveling at velocity v (more about this in Chapter 10):

$J\left(z,t\right)=J_0\cos \left(\omega t-\beta z\right)a_{z}A/m^2$

where J_0, is a constant amplitude, đ�œ” = 2đ�œ‹f is the radian frequency, and & is a constant to be found. Determine β as a function of đ�œ” and v such, that the given waveform satisfies both Eqs. (3) and (5). Begin with Eq. (5).