cos7xcos2x+sin7xsin2x=1/3
решите люди пожалуйста!!!!
cos7xcos2x + sin7xsin2x = 1/3
cos(7x-2x) = 1/3
cos5x = 1/3
5x = ±arccos(1/3) + 2πn
x = ±arccos(1/3)/5 + 2πn/5