  Explicit current-dependent expressions for anisotropic longitudinal and
transverse nonlinear magnetoresistivities are represented and analyzed on the
basis of a Fokker-Planck approach for two-dimensional single-vortex dynamics in
a washboard pinning potential in the presence of point-like disorder. Graphical
analysis of the resistive responses is presented both in the current-angle
coordinates and in the rotating current scheme. The model describes nonlinear
anisotropy effects caused by the competition of point-like (isotropic) and
anisotropic pinning. Nonlinear guiding effects are discussed and the critical
current anisotropy is analyzed. Gradually increasing the magnitude of isotropic
pinning force this theory predicts a gradual decrease of the anisotropy of the
magnetoresistivities. The physics of transition from the new scaling relations
for anisotropic Hall resistance in the absence of point-like pins to the
well-known scaling relations for the point-like disorder is elucidated. This is
discussed in terms of a gradual isotropizaton of the guided vortex motion,
which is responsible for the existence in a washboard pinning potential of new
(with respect to magnetic field reversal) Hall voltages. It is shown that
whereas the Hall conductivity is not changed by pinning, the Hall resistivity
can change its sign in some current-angle range due to presence of the
competition between i- and a-pins.
