C= 1/(2x3) + 1/(2x3) +1/(3x4)+ ... + 1/(99x100)
1/2x3+1/3x4+1/4x5+....+1/99x100=?
1/1x2 +1/2x3 +1/3x4+…+1/99x100
1/1x2 + 1/2x3 + 1/3x4 + ... + 1/99x100 + 1/100x101 = ...
A= 1/1x2+ 1/2x3 + 1/3x4 +............+ 1/99x100 và 1
A=1/1x2+1/2x3+1/3x4+......+1/99x100
1/1x2 + 1/2x3 + 1/3x4 +......+1/98x99 + 1/99x100
1/1X2 + 1/2X3 + 1/3X4 +...+1/99X100+ 1/100X101
tính:A=1/1x2+1/2x3+1/3x4+1/4x5+...+1/99x100