Решите уравниения 3cos^2x-5cosx+2=0

[latex]3cos^2x-5cosx+2=0\\cosx=u\\3u^2-5u+2=0\\D: 25-24=1\\u=\frac{5\pm 1}{6}\\\\u_1=1\\cosx=1\\x=2\pi n, \; n\in Z;\\\\u_2=\frac{2}{3}\\cosx=\frac{2}{3}\\x=\pm arccos\frac{2}{3}+2\pi n, \; n\in Z.[/latex]