Let e1 and e2 be unit vectors in the OXY-plane which make angles α and β withthe x-axis. Show that e1 = i cos α + jsin α, e2 = i cos β + jsin β and prove thatcos(α − β) = cos α cos β + sin α sin β
Let e1 and e2 be unit vectors in the OXY-plane which make angles α and β withthe x-axis. Show that e1 = i cos α + jsin α, e2 = i cos β + jsin β and prove thatcos(α − β) = cos α cos β + sin α sin β










