... 2 3 2sin 2x xx+ + − =tan cot 2 22(sin cos )23 3 2sin cosx xx xx x+⇔ + − =tan cotg 23 2 3 0x x⇔ + − =tan tan 0,53x = −tan3x kπ⇔ = − + π 13x =tan6x kπ⇔ = + π0,252Giải ... ==xxdxxxxdxI23233cos.2sin8cos.cos.sinđặt tanx = t dtttttdtIttxxdxdt +=+=+==3323222)1()12(8122sin;cos0,5Cxxxxdtttttdttttt+++=+++=+++=224333246tan21tanln3tan23tan41)33(1330,5http://tuyensinhtructuyen.edu.vn1 ... có 3 nghiệm x=-1/4 , x=1/2 và x=2. 02526 620 0tan( )tan 14os2x (t anx+1)xxI dx dxcπ ππ−+= = −∫ ∫ , 221 tan xcos 2x1 tan x−=+025http://tuyensinhtructuyen.edu.vnCâu...