Question

cos^2 a + tg(-a)ctg a

Answer 1

Ответ:

Объяснение:

cos^2 - tga * ctg a = cos^2 - 1 = - sin^2a

Answer 2

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

Ответ: - sin^2 a.