  The idea of determining the magnetic resonance condition in a rotating frame
of reference is being studied. In this frame, the rotating magnetic field
should be at rest. The 3D transformation that determines the transition to the
frame is found. The Dirac equation in a rotating electromagnetic field after
such a transition is obtained. The magnetic resonance condition is determined
by the stationarity of solutions. The connection between g-factor in the
anomalous magnetic moment and a constant in 3D transformation is established.
