3-1u(0) (0,)=1.5Ai2(0,)=3Ai(0,)=-3A l(∞)=211(∞)=0.5Ai2(∞)=1Aic(∞)=0 2i1(0,)=3A1(0)=18Ai2(0,) 0)=48 i4(∞)=5A1()=3A2(∞)=2A (∞)=0 3-3u2(t)=1332V1(1)=-1.33m4曲线略 3-4C=125/Fi(0,)=0u2(D)=10(1 3-5i1()=11.1+37e833A i2(t)=5.55e 8333t i(1)=1.1-1.85e333 3-6l2(t)=9-e33 3-7l1()=30+20e-130t()=-0.896-1304 曲线略 3-8l(0)=l2(∞)+[(0,)-a(0)e%=201-e t=0.12(0.1)=7.87 S闭合后,l2(t)=20-12.13e 5 3-9l()=-2.5+7.5e5T i()=-0625-0.935e25A i, (t=e a i,(t)=26 i, (t)=ea l()=8-8e2V 3-131()=1-%e 750t l2(t)=1.253－1 uC (0− ) = 6V i 1 (0+ ) =1.5A i 2 (0+ ) = 3A iC (0+ ) = −3A uC () = 2V i 1 () = 0.5A i 2 () =1A iC () = 0 3－2 i L (0+ ) = 3A i 1 (0+ ) =1.8A i 2 (0+ ) =1.2A uL (0+ ) = 4.8V i L () = 5A i 1 () = 3A i 2 () = 2A uL () = 0 3－3 uC (t) =13.3e −2 5tV iC (t) = −1.33e −2 5tmA 曲线略 3－4 C F i u t e V C t C 12.5 (0 ) 0 ( ) 10(1 ) 10000 − =  + = = − u t e V t C ( ) 10(1 ) −8 = − 3－5 i t e A i t e A t 8333 t 2 8333 1 ( ) 11.1 3.7 ( ) 5.55 − − = + = i t e A 8333 t 3 ( ) 11.1 1.85 − = − 3－6 ( ) 9 33. 3 u t e V t C − = − 3－7 u t e V i t e A t t C 1.1 2 1 0 1.1 2 1 0 4 4 ( ) 30 20 ( ) 0.896 −  −  = + = − 曲线略 3－8 u t u u u e e V t t C C C C ( ) ( ) [ (0 ) ( )] 20(1 ) −5 − =  + + −  = −  t = 0.1 uC (0.1) = 7.87V ( ) 20 12.13 10 0.1 S2 u t e V t C 闭合后， − （ − ） = − 3－9 ( ) 2.5 7.5 2.5 u t e V t C − = − + i t e A 2.5 t 0 ( ) 0.625 0.935 − = − − 3－10 i t e A i t e A t t 1 ( ) 2 ( ) 2 − − = = 3－11 i t e A u t e V t L t L 4 1 0 4 1 0 2 2 ( ) ( ) 4 −  −  = = − 3－12 ( ) 8 8 25 u t e V t C − = − 3－13 i t e A 750 t 0 6 ( ) 1 1 − = − ( ) 1.25 750 u t e V t L − =