dt di u1=L∴i(0-)=0u(0-)=0 dt u(0)= R,+R.R2=u(0 e(O+) u2(0+) RU R+r r+r i(0) i1(0) R+R u1(0) R+R i(0+ U R ua2(0)=-R2i1(0)= R+R UR u(0)=u2(0”)+u(0) 十 R,+R2R1+R2( ) 0 R R U R R R U R u (0 ) u (0 ) u (0 ) R R U R u (0 ) R i (0 ) i (0 ) R R U i (0 ) R R U i 0 R u (0 ) R R U u (0 ) i (0-) 0 u (0-) 0 dt di u L dt du i c 1 2 0 2 1 2 0 2 L R 2 c 1 2 0 2 R 2 2 L L 1 2 0 c 1 2 0 L 2 c 1 2 - 0 c c L L L c c = + + + = + = − + = − = − = − + = − + = = +  = = =  = = + + + + + + + − + ＋ － ＋ － uL(0+) 1 2 0 R R U + R2 ic(0+) 1 2 2 0 R R R U + ＋ － uR2(0+) iL(0 （b） +)