2)
cos 10°+sin 100° = Сos10° + Sin(90°+10°) = Cos10° + Cos10° = 2Cos10°
tg 20°+tg70° = (tg20° +tg70°)/(1 - tg20°tg70°) = tg90°/(1 - tg20°tg70°) -не существут
3)
tg(-225°) = -tg225° = -tg(180°+45°) = -tg45° = -1
Sin240° = Sin(180°+60°) = -Sin60° = -√3/2
Ctg150 ° = Ctg(180° -30°) = -Ctg30° = √3
1)
4П/3 = 4*60° = 240°