题目

1/1*3+1/3*5+```+1/(2n-1)(2n+1)怎样用裂项法求和?

提问时间：2021-09-16

答案

1/1*3+1/3*5+...+1/(2n-1)(2n+1)
=1-2/3+2/3-3/5+3/5-4/7+...+n/(2n-1)-(n+1)/(2n+1)
=1-(n+1)/(2n+1)
n/(2n+1)