Ответ:

cosx=-sqrt(3)/2

x=+-2/3П+2Пk

 

sqrt(2)cos2x=1

cos2x=sqrt(2)/2

2x=+-П/4+2Пk

x=+-П/8+Пk

 

сos(4x+П/8)=0

4x+П/8=П/2(2k+1)

4x=Пk+П/2-П/8=Пk+3П/8

х=Пk/4+3П/32

 

cos(x/2+П/3)=1

x/2+П/3=2Пk

x=4Пk+2П/3