Question

cos4x*cos2x+sin4x sin2x=1 помогите срочно.

Answer 1

cos4x*cos2x+sin4x*sin2x=1

cos(4x-2x)=1

cos2x=1

2x=2pi*k

x=pi*k; k принадлежит Z

Answer 2

cos4x*cos2x+sin4x sin2x=1
cos(4x-2х)= 1
cos 2x=1
cosx= 1/2
х= ± arccos 1/2 +2πn, n∈∑ 
х= ± π/3 + 2πn, n∈∑