1/1x2+1/2x3+1/3x4+............+1/8x9
1/1x2+1/2x3+1/3x4+...+1/8x9+1/9x10
1/2x4+1/4x6+1/6x8+...+1/96x98+1/98x100=?
1/2x4+1/4x6+1/6x8+...+1/96x98+1/98x100
(1/2x4+1/4x6+1/6x8+1/8x10)xy=1/3
tính:1/2x4+1/4x6+1/6x8+.....+1/96x98+1/98x100=.......
Tính nhanh:
1/1x2+1/2x3+1/3x4+1/3x5+..............1/8x9
Tính
1/2x4+1/4x6+1/6x8+...+1/96x98+1/98x100=?
Tính 1/(2x4) + 1/(4x6) + 1/(6x8) + ... + 1/(96x98) + 1/(98x100)
