作业帮一乘二分之1+ 2乘3分之1 +3乘四分之1……+2008乘2009分之一=2乘3分之1 +3乘四分之1……+2008乘2009分之一=-3减[-5+（1减0.2除5分之3）除-2]
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/03 01:47:17
![一乘二分之1+ 2乘3分之1 +3乘四分之1……+2008乘2009分之一=2乘3分之1 +3乘四分之1……+2008乘2009分之一=-3减[-5+（1减0.2除5分之3）除-2]](/uploads/image/z/132080-32-0.jpg?t=%E4%B8%80%E4%B9%98%E4%BA%8C%E5%88%86%E4%B9%8B1%2B+2%E4%B9%983%E5%88%86%E4%B9%8B1+%2B3%E4%B9%98%E5%9B%9B%E5%88%86%E4%B9%8B1%E2%80%A6%E2%80%A6%2B2008%E4%B9%982009%E5%88%86%E4%B9%8B%E4%B8%80%3D2%E4%B9%983%E5%88%86%E4%B9%8B1+%2B3%E4%B9%98%E5%9B%9B%E5%88%86%E4%B9%8B1%E2%80%A6%E2%80%A6%2B2008%E4%B9%982009%E5%88%86%E4%B9%8B%E4%B8%80%3D-3%E5%87%8F%5B-5%2B%EF%BC%881%E5%87%8F0.2%E9%99%A45%E5%88%86%E4%B9%8B3%EF%BC%89%E9%99%A4-2%5D)
一乘二分之1+ 2乘3分之1 +3乘四分之1……+2008乘2009分之一=2乘3分之1 +3乘四分之1……+2008乘2009分之一=-3减[-5+（1减0.2除5分之3）除-2]
一乘二分之1+ 2乘3分之1 +3乘四分之1……+2008乘2009分之一=
2乘3分之1 +3乘四分之1……+2008乘2009分之一=-3减[-5+（1减0.2除5分之3）除-2]
一乘二分之1+ 2乘3分之1 +3乘四分之1……+2008乘2009分之一=2乘3分之1 +3乘四分之1……+2008乘2009分之一=-3减[-5+（1减0.2除5分之3）除-2]
一乘二分之1+ 2乘3分之1 +3乘四分之1……+2008乘2009分之一
=1-1/2+1/2-1/3+...+1/2008-1/2009
=1-1/2009
=2008/2009
3减[-5+（1减0.2除5分之3）除-2]
3-[-5+(1-0.2÷3/5)÷（-2）]
=3-[-5+(1-0.2×5/3)÷（-2）]
=3-[-5+(1-1/3)÷（-2）]
=3-[-5+2/3÷（-2）]
=3-[-5-1/3]
=3-(-16/3）
=3+16/3
=25/3
原式=（1-1/2)+(1/2-1/3)+(1/3-1/4)+...+(1/2007-1/2008)+(1/2008-1/2009)
=1-1/2009
=2008/2009
1/1*2+1/2*3+1/3*4+....+1/2008*2009
=1-1/2+1/2-1/3+....+1/2008-1/2009
=1-1/2009
=2008/2009
1/2*3+1/3*4+....+1/2008*2009
=1/2-1/3+1/3-1/4+...+1/2008-1/2009
=1/2-1/2009
=2007/...
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1/1*2+1/2*3+1/3*4+....+1/2008*2009
=1-1/2+1/2-1/3+....+1/2008-1/2009
=1-1/2009
=2008/2009
1/2*3+1/3*4+....+1/2008*2009
=1/2-1/3+1/3-1/4+...+1/2008-1/2009
=1/2-1/2009
=2007/4018
-3-{-5+[1-0.2/(3/5)]/(-2)}
=-3-{-5+[1-1/5*5/3]/(-2)}
=-3-{-5+[1-1/3]/(-2)}
=-3-{-5+(2/3)/(-2)}
=-3-{-5+(2/3)*1/(-2)}
=-3-{-5-1/3}
=-3+5+1/3
=2+1/3
=7/3
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