1-1/2+1/3-1/4+.+1/50
来源:学生作业帮助网 编辑:六六作业网 时间:2024/09/10 17:31:11
1-1/2+1/3-1/4+.+1/501-1/2+1/3-1/4+.+1/501-1/2+1/3-1/4+.+1/501-1/2+1/3-1/4+……+(1/2n-1)-1/2n=1+1/2+1/3
1-1/2+1/3-1/4+.+1/50
1-1/2+1/3-1/4+.+1/50
1-1/2+1/3-1/4+.+1/50
1-1/2+1/3-1/4+……+(1/2n-1)-1/2n
=1+1/2+1/3+1/4+……+(1/2n-1)+1/2n
-2(1/2+1/4+1/6+1/8+...+1/2n)
=1+1/2+1/3+1/4+……+(1/2n-1)+1/2n
-(1/1+1/2+1/3+1/4+...+1/n-1+1/n)
即:抵消了前n项,剩下的是后n项是从1/(n+1)至1/2n
=1/(n+1)+1/(n+2)+1/(n+3)+...+1/(2n-1)+1/2n
1-1/2+1/3-1/4+.+1/50=1/26+1/27+1/28+.+1/50
请问你如何知道1/50是正的呢?我怎么觉得是负的,你这样问问题有意思?