Упростить выражение:

(1-cos² a) (1+ctg² a)

1/cos^2 (a) - 1/ctg^2 (a) = 1/cos^2 (a) - tg^2 (x) = 1/cos^2 (x) - sin^2 (x) / cos^2 (x) = 1-sin^2 (x) / cos^2 (x) = cos^2 (x) / cos^2 (x) = 1

a) 1.

ОДЗ: ctga≠0

cosa≠0

a≠пn

a≠п/2+2 пn

n∈z

1-sina/1+sina-1-2sina/cos^2 (a) = 1-sina/1+sina-1-2sina/1-sin^2 (a) = 1-sina/1+sina-1-2sina / (1-sina) * (1+sina) = ((1-sina) * (1-sina) - 1+2sina) / (1-sina) * (1+sina) = (1-2sina-sin^2 (a) - 1+2sina) / (1-sina) * (1+sina) = sin^2 (a) / cos^2 (a) = tg^2 (a)

ОДЗ: sina≠-1

cosa≠0

a≠-3 п/4+2 пn

a≠п/4+пn

n∈z