1.tg(20пи/3)= 2.tg(28пи/3)= 3.tg(-31пи/6)= 4.ctg(16пи/3)=
1. =tg(21π/3 - π/3)=tg(7π - π/3)= -tg(π/3)= -√3 2. = -tg(31π/6) = - tg(30π/6 + π/6)= -tg(5π + π/6) = = -tg(π/6)= - 1/√3 = -√3/3 3. =ctg(15π/3 + π/3)=ctg(5π + π/3) = ctg(π/3)= 1/√3 = √3/3