例 已知R=102,L,=5H,L2=2H,M=1H,求(t)和u2(t) R2 10 2t5 解 10V 0≤t≤1s 10t 0≤t≤1s 42(t)=M di, -10V 1≤t≤2s i1= 20-10t1≤t≤2s dt 0 2≤t 0 2≤t 100t+50V 0≤t≤1s u(t)=Ri+L di -100t+150V1≤t≤2s dr 0 2≤t