Tan 150° + cos 60° per tan 150° - cos 60°

(tan(180-30)+1/2)/(tan(180-30)-1/2)
=(-tan 30+1/2)/(-tan 30-1/2)
=(-(1/3)√3+1/2)/(-(1/3)√3-1/2)
=(-(2√3+3)/6) / ((-2/3 - 3)/6)
=(-2√3+3)/(-2√3 - 3), rasionlkn
=(-2√3+3)(-2√3+3)/(12-9)
=(12-12√3+9)/3
=(21-12√3)/3
=7-4√3