7/8+ 7/24+7/48+7/80+7/120+7/168

分类: 作业答案 • 2022-05-27 20:53:01

问题描述：

答

7/8 * (1+1/3+1/6+1/10+1/15+1/21)
=7/4 * (1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+1/(5*6)+1/(6*7))
=7/4 * (1-1/7)=3/2