1+ cos2 α-sin2 α

Question

1+ cos2 α-sin2 α

Answer 1

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))