Question

Решите плиз : 
1 )   4sin x cos x cos 2x = sin^2 4x
2) cos 2x + 4sin ^4 x = 8 cos^6 x
3)2sin^2 x + 1/4 cos^3 2x = 1
4)cos^2 x + cos^2 2x = cos^2 3x

Answer 1

2sin2xcos2x=sin^2 4x
sin4x=sin^2 4x
sin^2 4x - sin4x=0
t^2-t=0
t(t-1)=0
t1=0 t2=1
sin4x=0                    sin4x=1
4x= pi n  x= pi n/4      4x=pi/2+2pi n         x= pi/8 +pi n/4

Answer 2

щас проверю точно

Answer 3

cos 2x + 4 sin^4 x = 8 cos^6 x