1/8+1/24+1/48+1/120,简便算法,急

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1/8+1/24+1/48+1/120,简便算法,急

1/8+1/24+1/48+1/120,简便算法,急
1/8+1/24+1/48+1/120,简便算法,急

1/8+1/24+1/48+1/120,简便算法,急
1/8+1/24+1/48+1/120
=(30+10+5+2)/240
=47/240

1/8+1/24+1/48+1/120 =1/2*(1/2-1/4)+1/2*(1/4-1/6)+1/2*(1/6-1/8)+1/2*(1/8-1/10) =1/2*(1/2-1/4+1/4-1/6+1/6-1/8+1/8-1/10) =1/2*(1/2-1/10) =1/2*(5/10-1/10) =1/2*2/5 =1/5

1/8+1/24+1/48+1/80+1/120 =(1/2-1/4)/2+(1/4-1/6)/2+(1/6-1/8)/2+(1/8-1/10)/2+(1/10-1/12)/2 =[(1/2-1/4)+(1/4-1/6)+(1/6-1/8)+(1/8-1/10)+(1/10-1/12)]/2 =(1/2-1/12)/2、 =(5/12)/2、 =5/24