  We study dynamics of two coupled periodically driven oscillators. Important
example of such a system is a dynamic vibration absorber which consists of a
small mass attached to the primary vibrating system of a large mass.
  Periodic solutions of the approximate effective equation are determined
within the Krylov-Bogoliubov-Mitropolsky approach to get the amplitude profiles
$AOmega) $.
  Dependence of the amplitude $A$ of nonlinear resonances on the frequency $
\Omega $ is much more complicated than in the case of one Duffing oscillator
and hence new nonlinear phenomena are possible. In the present paper we study
metamorphoses of the function $A(\Omega) $ induced by changes of the control
parameters.
