Question

Помогите .............

Answer 1

a) 2tgx + (tgx - 1)² = 2tgx + tg²x - 2tgx + 1 = tg²x + 1 = 1/Cos²x

б) (tgy + Ctgy)(1 + Cosy)(1 - Cosy) = (tgy + Ctgy)(1 - Cos²y) = (tgy + Ctgy) * Sin²y=$(\frac{Siny}{Cosy}+\frac{Cosy}{Siny})*Sin^{2}y=\frac{Sin^{2}y+Cos^{2}y }{SinyCosy}*Sin^{2}y=\frac{1*Sin^{2}y }{SinyCosy} =\frac{Siny}{Cosy}=tgy$