Given the following voltage and current it 5 sin377t 40 de
     Given the following voltage and current:  i(t) = 5 sin(377t - 40 degree)A  v(t) = 10 cos(377t + 80 degree)v  Determine the phase relationship between i(t) and v(t).  v(t) leads i(t) by  degrees   
  
  Solution
i(t) = 5sin(377t - 40deg)
v(t) = 10cos(377t +80deg) = 10cos(377 - 40deg + 120deg)
Thus v(t) leads i(t) by 120degrees.

