y=Acos(2x)+Bsin(2X)

y'=-Asin2x+2Bcos2x, y''= -4Acos2x-4Bsin2x

-4Acos2x-4Bsin2x+2(-Asin2x+2Bcos2x0)+10(Acos 2x + Bsin2х)=-sin2x
(6A-4B)cos2x+(6B-4A)sin2x=2x+5

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