ЕГЭ !!!с1!!!Много БАЛЛОВ !!!!!!!!!2sin^4(2x)+cos(4x)-1=0
Б) [2П;3П]

2sin^42x+1-2sin²2x-1=02sin^42x-2sin²2x=02sin²2x(sin²2x-1)=0sin2x=0⇒2x=πn,n∈z⇒x=πn/2,n∈z2π≤πn/2≤3π4≤n≤6n=4⇒x=2πn=5⇒x=5π/2x=6⇒x=3πsin²2x=1sin2x=-1⇒2x=-π/2+2πk,k∈z⇒x=-π/4+πk,k∈z2π≤-π/4+πk≤3π8≤-1+4k≤129≤4k≤139/4≤k≤13/4k=3⇒x=-π/4+3π⇒x=11π/4sin2x=1⇒2x=π/2+2πm,m∈z⇒x=π/4+πm,m∈z2π≤π/4+πm≤3π8≤1+4m≤127≤4m≤117/4≤m≤11/4m=2⇒x=π/4+2π=9π/4