1/4x5x6+1/5x6x7十1/6ⅹ7x8十1/7x8x9
1个回答
关注
![]()
展开全部
是1/(4x5x6)+1/(5x6x7)十1/(6ⅹ7x8)十1/(7x8x9)吗？
咨询记录 · 回答于2023-02-01
1/4x5x6+1/5x6x7十1/6ⅹ7x8十1/7x8x9
好的
是1/(4x5x6)+1/(5x6x7)十1/(6ⅹ7x8)十1/(7x8x9)吗？
是的
1/(4x5x6)+1/(5x6x7)十1/(6ⅹ7x8)十1/(7x8x9)=1/6(1/4-1/5)+1/7(1/5-1/6)+1/8(1/6-1/7)+1/9(1/7-1/8)=1/(4/6)-1/(5*6)+1/(5*7)-1/(6*7)+1/(6*8)-1/(7*8)+1/(7*9)-1/(8*9)
1/(4x5x6)+1/(5x6x7)十1/(6ⅹ7x8)十1/(7x8x9)=1/6(1/4-1/5)+1/7(1/5-1/6)+1/8(1/6-1/7)+1/9(1/7-1/8)=1/(4/6)-1/(5*6)+1/(5*7)-1/(6*7)+1/(6*8)-1/(7*8)+1/(7*9)-1/(8*9)=1/2(1/4-1/6+1/6-1/8+1/5-1/7+1/7-1/9)-(1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9)=1/2(1/4-1/8+1/5-1/9)-(1/5-1/9)=1/8-1/16-1/10+1/18
1/(4x5x6)+1/(5x6x7)十1/(6ⅹ7x8)十1/(7x8x9)=1/6(1/4-1/5)+1/7(1/5-1/6)+1/8(1/6-1/7)+1/9(1/7-1/8)=1/(4*6)-1/(5*6)+1/(5*7)-1/(6*7)+1/(6*8)-1/(7*8)+1/(7*9)-1/(8*9)=1/2(1/4-1/6+1/6-1/8+1/5-1/7+1/7-1/9)-(1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9)=1/2(1/4-1/8+1/5-1/9)-(1/5-1/9)=1/8-1/16-1/10+1/18=1/16-4/9=(9-64)/144=-55/144
明白了吗？亲
不好意思订正一下正确答案是1/(4x5x6)+1/(5x6x7)十1/(6ⅹ7x8)十1/(7x8x9)=1/6(1/4-1/5)+1/7(1/5-1/6)+1/8(1/6-1/7)+1/9(1/7-1/8)=1/(4*6)-1/(5*6)+1/(5*7)-1/(6*7)+1/(6*8)-1/(7*8)+1/(7*9)-1/(8*9)=1/2(1/4-1/6+1/6-1/8+1/5-1/7+1/7-1/9)-(1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9)=1/2(1/4-1/8+1/5-1/9)-(1/5-1/9)=1/8-1/16-1/10+1/18=1/16-2/45=13/720
不好意思订正一下正确答案是1/(4x5x6)+1/(5x6x7)十1/(6ⅹ7x8)十1/(7x8x9)=1/6(1/4-1/5)+1/7(1/5-1/6)+1/8(1/6-1/7)+1/9(1/7-1/8)=1/(4*6)-1/(5*6)+1/(5*7)-1/(6*7)+1/(6*8)-1/(7*8)+1/(7*9)-1/(8*9)=1/2(1/4-1/6+1/6-1/8+1/5-1/7+1/7-1/9)-(1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9)=1/2(1/4-1/8+1/5-1/9)-(1/5-1/9)=1/8-1/16-1/10+1/18=1/16-2/45=(45-32)/(16*45)=13/720
最后一段是正确答案
明白了吗？亲
已赞过
评论
收起
你对这个回答的评价是？
