Question

Решите уравнение?chj

Answer 1

6cos^2x-9cosx+3＝0
D＝81-72＝9
Cosx＝9+3/12＝1
X1＝ 0+2Пk＝2Пk , k є z (k принадлежит z )
Cosx＝9-3/12＝0.5
X2＝П/3+2Пk
X3＝-П/3+2Пk

Answer 2

$6cos^2x-9cosx+3=0 \\D=81-4*6*3=9=3^2 \\cosx= \frac{9+3}{12}=1 \\x_1=0+2\pi n=2\pi n \\cosx=\frac{9-3}{12}=\frac{1}{2} \\x_2= \frac{\pi}{3}+2\pi n \\x_3= -\frac{\pi}{3}+2\pi n$