仓鼠快死的前一段时间:求和(数列)

来源:百度文库 编辑:查人人中国名人网 时间:2024/05/08 01:10:20
求和:
1/(n+1)+1/(n+2)+1/(n+3)+ ……+1/(2n-1)+1/2n
(n>1)

解:原式=(1/(n+1)+1/2n)*n/2
=(2n+n+1)/(2n*(n+1)*n/2
=(3n+1)/(4*(n+1)