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{5pm 1}{6}\\u_1=1\cosx=1\x=2pi n, ; nin Z;\\u_2=frac{2}{3}\cosx=frac{2}{3}\x=pm arccosfrac{2}{3}+2pi n, ; nin Z.[/latex]