化简：1/(n+1)(n+2)+1/(n+2)(n+3)+1/(n+3)(n+4)

分类: 作业答案 • 2021-12-19 14:56:50

问题描述：

答

1/(n+1)(n+2)+1/(n+2)(n+3)+1/(n+3)(n+4)
=1/(n+1)-1/(n+2)+1/(n+2)-1/(n+3)+1/(n+3)-1/(n+4)
=1/(n+1)-1/(n+4)
=4/(n+1)(n+4)