Ответы и объяснения

2011-04-25T02:11:48+04:00

1+ cos2 α-sin2 α = (cos^2(α)+sin^2(α)) + (cos^2(α)-sin^2(α)) - 2*sin(α)*cos(α) =

= 2*cos^2(α)- 2*sin(α)*cos(α) = 2*cos(α) * (cos(α)-sin(α))