A.30° B.120° C.45° D.90°
单项选择题已知正弦电压ul=80sinωtV,u=100sin(ωt+36.9°)V,则u-ul为()。
A.60sin(ωt+90°)V B.60sin(ωt-90°)V C.60sin(ωt+36.9°)V D.20sin(ωt+36.9°)V
单项选择题正弦交流电流i1=6sinωtA,i2=8sin(ωt+π)A,则下列表达式正确的是()。
A.i1-i2=-2sinωtA B.i2-i1=14sin(ωt+π)A C.i1+i2=14sin(ωt+π)A