3. Damped oscillation and forced oscillation in an RlC circuit R R q L E;△U L E;△U 8=a coso,t RlC circuit -qe-ry2L cos(at+) Forced oscillation o'=V2-(R/2L3. Damped oscillation and forced oscillation in an RLC circuit L C I q i  U R RLC circuit 2 2 2 0 ( 2 ) cos( ) R L q q e t Rt L            Forced oscillation L C I q i  U R ~ t d   cos  0