  The paper is devoted to the analysis of the systematic deviations between the
classical formula for the rate of secular apsidal motion in close binaries and
the formula established within the framework of the theory of dynamic tides.
The basic behaviour is found to be governed by the dependency of the forcing
frequencies on the orbital period and the rotational angular velocity,
irrespective of the stellar model. For binaries with short orbital periods a
good agreement between the classical apsidal-motion formula and the formula
established within the framework of the theory of dynamic tides is only
possible for certain values of the rotational angular velocity.
