(t) 2)t.0 并求得2()=1 )t?0( a()=c (Se-S, 2 )u(t) RR S,-S2 i(1)=C CV e- u并求得 0 1 2 1 2 1 ( ) ( ) 0 s t s t L V i t e e t L s s = − − … 0 1 2 1 2 1 2 ( ) ( ) 0 L s t s t C di V v t L s e s e t dt s s = = − − ? 0 0 1 2 1 2 1 2 1 ( ) ( ) ( ) C s t s t R v V i t s e s e u t R R s s = = − − 0 2 2 1 2 1 2 1 2 ( ) ( ) ( ) C s t s t C dv CV i t C s e s e u t dt s s = = − − , R i v t 0 L i m t 2 m t C i