Question

1 задание, 1 пример!!!!!!!

Answer 1

$cos5x+cosx=0\\ \\ 2cos(\frac{5x+x}{2} )*cos(\frac{5x-x}{2} )=2cos3x*cos2x=0\\ \\ 1аcos3x=0\\ 3x=\frac{\pi}{2} +\pi n\\ x_1=\frac{\pi}{6} +\frac{\pi n}{3} \\ \\ 2аcos2x=0\\ 2x=\frac{\pi}{2} +\pi n\\ x_2=\frac{\pi}{4} +\frac{\pi n}{2}$