Question

помогите с решением

Answer 1

на фото..........................................

Answer 2

{cos2x=1/2
{sin3x=-1

1)cos2x=1/2
2x=±π/3+2πn
x=±π/6+πn

2)sin3x=-1
3x=-π/2+2πk
x=-π/6+2πk/3

3)-π/6+2πk/3=-π/6+πn
2πk/3=πn
n=2k/3
3n=2k

4)-π<-π/6+2πk/3<π
-π+π/6<2πk/3<π+π/6
-5π/6*3/2π<k<7π/6*3/2π
-5/4<k<7/4
k={-2;-1;0;1}