а) cos^4t = cos2tcos^2tcos2t^2 = 1−sin2t1-sin^2t1−sin2t^2 = 1 - 2sin^2t + sin^4t
б) sint*cost = sin2t2t2t/2
а) cos^4t = cos2tcos^2tcos2t^2 = 1−sin2t1-sin^2t1−sin2t^2 = 1 - 2sin^2t + sin^4t
б) sint*cost = sin2t2t2t/2