Use the trig identity
sin(A)cos(B) + cos(A)sin(B) = sin(A+B)
to get the following:
sin(83)cos(7) + cos(83)sin(7) = sin(83+7)
sin(83)cos(7) + cos(83)sin(7) = sin(90)
sin(83)cos(7) + cos(83)sin(7) = 1
