求数列{1/(2n-1)(2n+3)}的前n项和Sn
问题描述：
求数列{1/(2n-1)(2n+3)}的前n项和Sn
分母是(2n-1)(2n+3)
答
1/(2n-1)(2n+3)=1/4*[1/(2n-1)-1/(2n+3)]数列{1/(2n-1)(2n+3)}的前n项和Sn=1/4*[1-1/5+1/3-1/7+1/5-1/9+----------+1/(2n-3)-1/(2n+1)+1/(2n-1)-1/(2n+3)]=1/4*[1+1/3-1/(2n+1)-1/(2n+3)](接下去化简下）...