1/3×2/5=1/3-1/5同理1/5×2/7=1/5-1/7后面类推得：所以原式=1/3 × 2/5+1/5 ×2/7+1/7 ×2/9+……1/99 × 2/101=(1/3-1/5)+(1/5-1/7)+……+(1/99-1/101)=1/3-1/101=98/303 ∵每一项都是1/(2n+1)×2/(2n+3)的形式,n...