cos α = √(1 - sin² α) = √(1 - (12/13)²) = √(1 - 144/169) = √(25/169) = 5/13
tg α = sin α / cos α = (12/13) / (5/13) = 12/5
ctg α = 1 / tg α = 5/12
Ответ: cos α = 5/13, tg α = 12/5, ctg α = 5/12