(1).
周期：T=2π/100π=0.02
频率：f=1/T=50
初相：π/3
(2).
当t=0时,i=5sin(π/3)=2.5√3
当t=1/600时,i=5sin(π/6+π/3)=5sin(π/2)=5
当t=1/150时,i=5sin(2π/3+π/3)=5sin(π)=0
当t=7/600时,i=5sin(7π/6+π/3)=5sin(3π/2)=-5
当t=1/60时,i=5sin(5π/3+π/3)=5sin(2π)=0