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1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110=多少的简便运算怎么还没来答案
题目详情
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110=多少的简便运算
怎么还没来答案
怎么还没来答案
▼优质解答
答案和解析
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110
=1/(1×2)+1/(2×3)+1/(3×4)+...+1/(10×11)
=1-1/2+1/2-1/3+1/3-1/4+...+1/10-1/11
=1-1/11
=10/11
=1/(1×2)+1/(2×3)+1/(3×4)+...+1/(10×11)
=1-1/2+1/2-1/3+1/3-1/4+...+1/10-1/11
=1-1/11
=10/11
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