а) (1 - sin^2(a))/cos^2(a) = cos^2(a)/cos^2(a) = 1б) (1 - cos^2(a))/(1 - sin^2(a)) = sin^2(a)/cos^2(a) = tan^2(a)в) (1 + tan^2(a)) - sin^2(a) = sec^2(a) - sin^2(a) = 1г) (cot^2(a) + 1) * sin^2(a) - cos(a) = csc^2(a)sin^2(a) - cos(a) = 1 - cos(a)
а) (1 - sin^2(a))/cos^2(a) = cos^2(a)/cos^2(a) = 1
б) (1 - cos^2(a))/(1 - sin^2(a)) = sin^2(a)/cos^2(a) = tan^2(a)
в) (1 + tan^2(a)) - sin^2(a) = sec^2(a) - sin^2(a) = 1
г) (cot^2(a) + 1) * sin^2(a) - cos(a) = csc^2(a)sin^2(a) - cos(a) = 1 - cos(a)