3. The electromagnetic wave equation for a wave that propagates along z-axis in the positive direction, and oscillates in the x-direction has the form: where c 1s a constant, 1s the dielectric constant, is the conductivity, and eo is the permittivity of vacuum. The general trial solution to this equation can be written as: Using this expression show that index of refraction is generally a complex number, and SN YO oG (Ui