1/1*3+1/3*5+1/5*7+.+1/99*101

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1/1*3+1/3*5+1/5*7+.+1/99*1011/1*3+1/3*5+1/5*7+.+1/99*1011/1*3+1/3*5+1/5*7+.+1/99*1011/[n(n+2)]={(1/n

1/1*3+1/3*5+1/5*7+.+1/99*101
1/1*3+1/3*5+1/5*7+.+1/99*101

1/1*3+1/3*5+1/5*7+.+1/99*101
1/[n(n+2)]={(1/n)-[1/(n+2)]}/2
所以原式等于0.5×（1/1-1/3+1/2-1/4+1/3-1/5+……+1/99-1/101）
=0.5×[（1/1+1/2+1/3+……+1/99）-（1/3+1/4+1/5+……+1/101）]
=0.5×（1+1/2-1/100-1/101）=14949/20200
1楼中间相多去了几项

原式=1/2*（1-1/3+1/3-1/5+.......+1/99-1/101)=1/2*(1-1/101)=1/2*100/101=50/101

1-3+5-7+... (1+1/3+1/5+1/7)*(1/3+1/5+1/7+1/9)-(1+1/3+1/5+1/7+1/9)*(1/3+1/5+1/7) 简算(1+1/3+1/5+1/7)*(1/3+1/5+1/7+1/9)-(1+1/3+1/5+1/7+1/9)*(1/3+1/5+1/7) 简便计算 1/1*3+1/1*3*5+1/1*3*5*7+1/1*3*5*7*9-73/945 (1/3+1/5+1/7)*(1/5+1/7+1/9)-(1/3+1/5+1/7+1/9)*(1/5+1/7)=? 1/3+1/5+1/7+.+1/2n+1 1/1*3*5+1/3*5*7+1/5*7*9.+1/95*97*99 1/1×3+1/3×5+1/5×7+1/7×9.+1/2011×2013 简算:1/1*3+1/3*5+1/5*7+1/7*9+1/9*11 1/1*3+1/3*5+1/5*7+1/7*9+...1/17*19= 计算1/(1×3)+1/(3×5)+1/(5×7)+1/(7×9)+.+1/(19×21) 1/1×3+1/3×5+1/5×7+1/7×9+.+1/2013×2015 1/1*3+1/3*5+1/5*7+1/7*9+.+1/101*103 帮帮忙1/1*3+1/3*5+1/5*7+1/7*9+...1/99*101 1/1*3+1/3*5+1/5*7+1/7*9+1/49*51= 计算：1/1×3+1/3×5+1/5×7+1/7×9``````+1/2001×2003 (1*3)/1+(3*5)/1+(5*7)/1+(7*9)/1+(9*11)/1 1/1*3+1/3*5+1/5*7+1/7*9+1/9*11 (1*3)/1+(3*5)/1+(5*7)/1+(7*9)/1+(9*11)/1