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麻烦知道人士帮忙解决一下,万分感谢!在自然数1~100中找出10个不同的数,使这10个数的倒数和等于1
提示:1/(1*2)=1-1/2 1/(2*3)=1/2-1/31/(3*4)=1/3-1/4
1=(1-1/2)+(1/2-1/3)+(1/3-1/4)+1/4
人气:388 ℃ 时间:2019-09-09 18:08:19
解答
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/10
=1/(1×2)+1/(2×3)+1/(3×4)+1/(4×5)+1/(5×6)+1/(6×7)+1/(7×8)+1/(8×9)+1/(9×10)+1/10
=(1 - 1/2)+(1/2 - 1/3)+(1/3 - 1/4)+……+(1/9 - 1/10)+1/10
=1 - 1/10 +1/10
=1
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