sin^4 x/2 - cos^4 x/2= 1/2
(sin^2 x/2 - cos^2 x/2)(sin^2 x/2 +cos^2 x/2)= 1/2
- cos x = 1/2,
cosx= -1/2
x = ±2Pi/3 +2Pin, n€Z
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#1)
(1- cos^2x)/ sin x=1
sin^2x/ sin x= 1,
sin x= 1
x= Pi/2 + 2Pin,n€Z
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№7
sin 6x- sin2x= 0,
2sin 2x * cos4x=0
sin2x=0, 2x= Pin, x = Pin/2, n€Z
cos 4x=0, 4x=Pi/2 +Pik, x= Pi/8 + Pik/ 4, k€Z