tg (-225градусов) = -tg 225 = -tg (270-45) = - сtg 45 = -1.
tg (-315) = - tg 315 = - tg (360 - 45) = tg 45 = 1
tg (-225градусов) = -tg 225 = -tg (270-45) = - сtg 45 = -1.
tg (-315) = - tg 315 = - tg (360 - 45) = tg 45 = 1