电路相量计算问题，图中的题是怎么算的？

Question

如题所述

Answer 1

Z=√(R^2+(Xl-Xc)^2]
=√[10^2+(10-20)^2]
=10√2
Z与R的夹角为arctan[(Xl-Xc)/R]=arctan[(10-20)/10]=-45°
U=50
I=U/Z
=50/(10√2)
=3.54A
U与R的夹角为30°
U与Z的夹角为：30°-(-45°)=75°
∴I=3.54∠75°A