  The analytical and numerical study of the angular dependence of
magnetoresistance in layered quasi-two-dimensional (Q2D) metals is performed.
The harmonic expansion analytical formulas for the angular dependence of
Fermi-surface cross-section area in external magnetic field are obtained for
various typical crystal symmetries. The simple azimuth-angle dependence of the
Yamaji angles is derived for the elliptic in-plane Fermi surface. These
formulas correct some previous results and allow the simple and effective
interpretation of the magnetic quantum oscillations data in cuprate
high-temperature superconducting materials, in organic metals and other Q2D
metals. The relation between the angular dependence of magnetoresistance and of
Fermi-surface cross-section area is derived. The applicability region of all
results obtained and of some previous widely used analytical results is
investigated using the numerical calculations.
