XL=ωL=2πυL=2*50*π*12,7=1270π Ω
tgφ=XL/R=1270π/3=423,33π=>φ=arctg423,33π
Z=√(R²+XL²)=√(9+161,29)≅13 Ω
I=U/Z=100/13=7,7 A
i=Imax*sin(ωt+φ)=7,7√2sin(100πt+arctg423,33π) (A)
sinφ=XL/Z=1270π/13=97,7π
sinφ=UL/U=>UL=Usinφ=100*97,7π=9770π V
u=ULmax*sin(ωt+φ)=9770π√2sin(100π+arctg423,33π) (V)