Question

(Cosальфа-sinальфа)(cosальфа+sinальфа)/cos2альфа

Answer 1

Ответ:

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Answer 2

Ответ:

(Cos(x) - Sin(x))(Cos(x)+Sin(x))/Cos(2x) =

= (Cos(x)^2 - Sin(x)^2)/Cos(2x) =

= Cos(2x)/Cos(2x) = 1

примечание : Cos(2x) = Cos(x)^2 - Sin(x)^2