In Figure P154 L1 25mH; L2 30 mH, and M 25mH. The output voltage

In Figure P15–4 L1 ¼ 25mH; L2 ¼ 30 mH, and M ¼

25mH. The output voltage is observed to v2ðtÞ ¼ 50 cos 1000t V when the output terminals are open-circuited

ði2ðtÞ ¼ 0Þ. Find v1ðtÞ.