Нуждаюсь в помощи cos(-п/6)tg 45+sin(-п/3)ctg 45

cos(-π/6)tg(45) + sin(-π/3)ctg(45) = cos(-π/6)tg(π/4) + sin(-π/3)ctg(π/4) = (√3/2)*1 + (-√3/2)*1 = 0