( X 1 ) X N ( 1 X )( X 1 ) > X N 1- X > X N X + X - 1 < - N 1 1 54 X X 4 4 N ( VỠ ĐK X > 0 & X 4)1 1 2 54 X 2 4 N=> N < 1BÀI II
3/ P.( x 1 ) x n ( 1 x )( x 1 ) > x n
1- x > x n x + x - 1 < - n 1 1 5
4 x x 4 4 n ( vỡ đk x > 0 & x 4)
1 1
2