  The optical conductivity along and perpendicular to the planes is calculated
assuming strong k-dependence of the scattering rate and the c-axis hopping
parameter. Closed analytical expressions for the optical conductivy along these
directions are obtained, and are shown to be integrable at low and high
frequencies. A large and qualitatively different frequency dependence for both
polarizations follows directly from the model. The expression for the in-plane
conductivity has an effective scattering rate proportional to frequency, and
can be easily generalized to provide a simple analytical expression, which may
replace the Drude formula in the case of non-Fermi liquids.
