Question

1-sin^4t-cos^4t/2sin^4t

Answer 1

Числитель =
=1 - Sin^4 t - Cos^4 t = (1 - Sin²t)(1+Sin²t) - Cos^4t=
=Cos²t(1 + Sin²t) - Cos^4 t= Cos²t +Sin²tCos²t - Cos^4 t=
= Cos²t(1 - Cos²t) + Sin²tCos²t = Cos²t·Sin²t+Sin²tCos²t=
=2Sin²tCos²t
При делении на 2Sin^4 t  дробь можно сократить на 2 Sin²t
Ответ:Сtg² t