1/1X2+1/2X3+1/3X4+1/4X5+1/5X6……1/2007X2008
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+……+1/2007-1/2008
=1-1/2008
=2007/2008解释。加10。1/(1×2)=1-1/21/(2×3) = 1/2 - 1/3……1/(2007×2008) = 1/2007 - 1/2008然后中间的都约去了！