1/2*1/3+1/3*1/4+1/4*1/5+……1/2002*1/2003=1/2-1/3+1/3-1/4+1/4-.-1/2002+1/2002-1/2003

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/06 00:49:54

1/2*1/3+1/3*1/4+1/4*1/5+……1/2002*1/2003=1/2-1/3+1/3-1/4+1/4-.-1/2002+1/2002-1/2003
1/2*1/3+1/3*1/4+1/4*1/5+……1/2002*1/2003=1/2-1/3+1/3-1/4+1/4-.-1/2002+1/2002-1/2003

1/2*1/3+1/3*1/4+1/4*1/5+……1/2002*1/2003=1/2-1/3+1/3-1/4+1/4-.-1/2002+1/2002-1/2003
很简单的嘛
看式子
1/2n*1/2n+1=1/2n(2n+1)
1/2n-1/2n+1=1/2n(2n+1)
n>=1的整数
这样两边的式子就是相等的

1/N*(N+1)=1/N-1/(N+1)

1/n-1/(n+1)=(n+1-n)/n*(n+1)=1/n(n+1)

1/n*1/(n+1)=1/[n*(n+1)]=[(n+1)-n]/[n*(n+1)]=
1/n-1/(n+1)
明白了吗?

1/2*1/3+1/3*1/4+1/4*1/5+……1/2002*1/2003=1/2-1/3+1/3-1/4+1/4-......-1/2002+1/2002-1/2003
=1/2-1/2003
=2001/4006