R>2, P1,p2不等的负实根 (t=0) e +A R+ 2 (0)=U→>A1+A2=U/0 d C(0+)= i(0 0→PA,+PA,=0 dt C U 2 0 dt P1 P2-pRepmd e P C一. 2 p 1 , p 2 不等的负实根 CL R  p t p t C u e e 1 2 = A 1 + A 2 0 A 1 A 2 0 u C ( 0 ) = U → + = U + 0 A A 0 (0 ) (0 ) dd = → 1 1 + 2 2 = − = + + P P Ci tuC 0 2 1 1 0 2 2 1 2 A1 A U P PP U P P P −− = − = ( ) 1 2 2 1 2 1 0 p t p t C P e P e P P U u − − = Ci dt du d t du i C C C = − = − ( t=0) R L C +- i u c u L+-