1/2+1/6+1/12+1/20+1/30+1/42等于多么的过程

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1/2+1/6+1/12+1/20+1/30+1/42等于多么的过程

1/2+1/6+1/12+1/20+1/30+1/42等于多么的过程
1/2+1/6+1/12+1/20+1/30+1/42等于多么的过程

1/2+1/6+1/12+1/20+1/30+1/42等于多么的过程
1/2+1/6+1/12+1/20+1/30+1/42
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1-1/7
=6/7

=1/(1*2)+1/(2*3)+..+1/(6*7)=1/1-1/2+1/2-1/3+..+1/6-1/7=1-1/7=6/7

1/2+1/6+1/12+1/20+1/30+1/42
=1/2+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+(1/6-1/7)
=1/2+1/2-1/7
=6/7