Tg5x*sin10x + cos10x -cos20x=0 Незнаю как начать
Tg5x * sin10x + cos10x - cos20x = 0 sin5x / cos5x * (2sin5x * cos5x) + cos10x - cos20x = 0 2sin^2 5x + cos^2 5x - sin^2 5x - cos2 0x = 0 cos^2 5x + sin^2 5x - cos20x = 0 1 - cos20x = 0 cos20x = 1 20x = 360град * n x = 18град * n