Question

Упростите выражения​​​​

Answer 1

a)

(1/(1+ctg²α) + cos²α)* tg²α = tg²α/(1/sin²α) + sin²α = tg²α*sin²α + sin²α = sin²α(tg²α+1) =sin²α(1/cos²α) = tg2α

б)

(tg²α/(1+tg²α)  + cos²α)* cos²α = (tg²α/(1/cos²α)  + cos²α)* cos²α = (sin²α  + cos²α)* cos²α = cos²α