已知u1=10sin(314t+π/2)V

表示向量的上箭头打不出来，以下用右箭头代替。1、u = u1 + u2；u1→ （π/2，10 )，u2→ （ π/3，5√3 )；u→ = u1→ + u2→ = (π/2 +π/3，10 +5√3 )Asin(5π/6) = 10 +5√3；A = (10 + 5√3 )/sin(5π/6) =( 10 + 5√3 )/sin(π/6) = 20 + 10√3u1 + u2 = 10( 2 +√3 )sin( 314t +5π/6 )；2、u = u1 - u2；u→ = u1→ - u2→ = ( π/2 - π/3，10 - 5√3 )；Asin(π/6) = 10 - 5√3；A = ( 10 - 5√3 )/sin(π/6) = 20 - 10√3u1 - u2 = 10( 2 - √3 )sin( 314t + π/6 )；

希望以下回答对您有帮助：u₁+u₂=10[sin(314t+π/2)+sin(314t+π/3)]=10*2sin[314t+(π/2+π/3)/2]cos[π/2-π/3)/2]=20cos(π/12)sin(314t+5π/12)=5(√6+√2)sin(314t+5π/12)u₁-u₂=10[sin(314t+π/2)-sin(314t+π/3)]=10*2cos[314t+(π/2+π/3)/2]sin[(π/2-π/3)/2]=20sin(π/12)cos(314t+5π/12)=5(√6-√2)sin(314t+11π/12)