()=(0)+[(5d5 例2已知:u(0)=0和i(t),C=1F,求u(t)并画波形。 (A) 解:分段求积分 0-1:(t)=(0)+i(55 0 3;/4t(s) 0+ u 1-3:(t)=u(1)+(-5+2)d 05 +2t-1 0 t(s) M2)=Ⅳ7(3例2 已知:u(0)=0和i(t)，C=1F，求 u(t)并画波形。 u(V) 1 2 3 4 t(s) 0 0.5 1 t(s) i(A)1 −1 0 1 2 3 4 解：分段求积分： 0-1： 2 0 0 2 1 0 1 0 d t i( )d C u(t ) u( ) t t = + = = +       1-3： 2 1 2 1 1 2 2 1 = − + − = + − +  t t u(t ) u( ) ( )d t   u( ) V 2 1 1 = u( ) V 2 1 u( 2 ) =1V 3 =  = + t t i d C u t u t 0 ( ) 1 ( ) ( ) 0  