решите пожалуйста!!!!!!!!
COS(A+П/4)*COS(A-П/4)

COS(A+П/4)*COS(A-П/4) = (1/2)* [cos(α + π/4 - α + π/4) + cos(α + π/4 + α - π/4)] == (1/2)* [ cos(π/2) + cos2α] = (1/2)*cos(2α)