Найти производную функции f' (x) = (3-sin3x) * cos3x

F (x) = (3 - sin3x) cos3x

f' (x) = - 3cos3x * cos3x - 3sin3x (3 - sin3x) =

= - 3 (cos3x) ^2 - 9sin3x + 3 (sin3x) ^2 =

= - 3 + 3 (sin3x) ^2 + 3 (sin3x) ^2 - 9sin3x =

= 6 (sin3x) ^2 - 9sin3x - 3