第1个回答 推荐于2021-01-22
1-1/2-1/6-1/12-...-1/90
=1-(1/2+1/6+1/12+...+1/90)
=1-(1/1*2+1/2*3+1/3*4+...+1/9*10)
=1-(1-1/2+1/2-1/3+1/3-1/4+.....+1/9-1/10)
=1-(1-1/10)
=1-1+1/10
=1/10本回答被提问者和网友采纳
=1-(1/2+1/6+1/12+...+1/90)
=1-(1/1*2+1/2*3+1/3*4+...+1/9*10)
=1-(1-1/2+1/2-1/3+1/3-1/4+.....+1/9-1/10)
=1-(1-1/10)
=1-1+1/10
=1/10本回答被提问者和网友采纳
第2个回答 2011-10-15
1-1/(1*2)-1/(2*3)-....-1/(9*10)=1/10
第3个回答 2011-10-12
1-1/2-1/6-1/12-...-1/90
=1-(1-1/2)-(1/2-1/3)+...-(1/9-1/10)
=1/10
=1-(1-1/2)-(1/2-1/3)+...-(1/9-1/10)
=1/10
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