2cos2(x+π/6)-3cos(x+π/6)+1=0

Question

2cos2(x+π/6)-3cos(x+π/6)+1=0

Answer 1

Cos(x+ π/6)=t
2t^2-3t+1=0
D=9-4*2=1>0 (1)
t1= 3-1/4=0,5
t2=3+1/4=1
cos( x+π/6)=0,5 или cos(x+ π/6)=1
дальше не помню, извини