1/1*2+1/2*3+1/3*4+1/4*5+...1/39*40
=1-1/2+1/2-1/3+1/3-1/4+……+1/39-1/40
=1-1/40
=39/40
1/1*2+1/2*3+1/3*4+1/4*5+...1/39*40怎么计算?
1个回答
相关问题
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1/2+(1/3+2/3)+(1/4+2/4+3/4)+...+(1/40+2/40+3/40+...+39/40)
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2\1+(3\1+3\2)+(4\1+4\2+4\3)+.+(40\1+40\2+.+40\38+40\39)
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1/1×2+1/2×3+1/3×4+1/4×5+...+1/39×40
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1/1x2/1+2/1x3/1+3/1x4/1+4/1x5/1...+39/1x40/1怎么算还有过程
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（2010•东莞）计算 5.61-[2/5]+4.39-1[3/5] [4/15]÷[1-（[1/5]+[1/3]）]