1/49+1/914+1/1419+1/1924……+1/79*84

hhl682022-10-04 11:39:541条回答

1/4*9+1/9*14+1/14*19+1/19*24……+1/79*84
请尽快解答,（最好把1/5*8+1/8*11+1/11*14+……+1/98*101也算出来）要过程,

已提交，审核后显示！提交回复

chendexun 共回答了15个问题 | 采纳率93.3%: 1/4*9+1/9*14+1/14*19+1/19*24……+1/79*84
=[(1/4-1/9)+(1/9-1/14)+……+(1/79-1/84)]/5
=(1/4-1/84)/5
=(20/84)/5
=1/21
1/5*8+1/8*11+1/11*14+……+1/98*101
=[(1/5-1/8)+(1/8-1/11)+……+(1/98-1/101)]/3
=(1/5-1/101)/3
=(96/505)/3
=32/505; 1年前

1/4*9+1/9*14+1/14*19+1/19*24……+1/79*84