... 322322x3xdxI (1) 44(x1)(x1)=+ ị Xét tích phân: 2222222222xdx1[(x1)(x1)]dx 112 1Jdx44(x1)(x1)(x2)x1(x1) 11 x 111 x12xlnClnC(2)4x1x1x14x1x1éù+ +- ===++êú +ëûỉưỉư =-+ -+ =-+ ç÷ç÷ -+ ++ - èøèøịịị ... n1nnn12n2n1nn1n2n1tt2nJ(2n1)J2(n1)J(2n3)J(t1)(t1)1tJ2n3)J2(n1)(t1) +- - - - Û= -= éùÛ =-= +- êú ëû Do đó: 21 21tJJ2t1ỉư =-+ ç÷ - èø 3 21 222221t1t1tIJ3J3J442(t1)(t1)t1ìüéù ... 2222(x3)(x1) 1, 2 1( x3)(x1 )11 12(x3)(x1)4x1x3(x3)(x1) +-+ éù=êúëû +-+ éùéù= =- êúêú++++++ëûëû 222222 11 211 1(x3)(x1 )1 4(x1)(x3)4(x1)(x3)(x1)(x3)(x1)(x3)1dxdxdxdx4x1x3(x1)(x3) 11 11x32x4ln|x1|ln|x3|ClnC.4x1x34x1(x1)(x3)éùéù +-+ =-+ =-+ êúêú++++++++ëûëûéù =-+ +êú++++ëûéù++éù=...