Вопрос 11 класс математика

cos a = - 1/V6sin^2 a = 1 - cos^2 a = 1 - (-1/V6)^2 = 1 - 1/6 = 5/6ctg^2 a = (cos a / sin a)^2 = ((-1/V6) / (5/6))^2 = (- V6/5)^2 = 6/255 * 6ctg^2 a * sin^2 a = 30 * 6/25 * 5/6 = 30/5 = 6