式子如下:1 1 1 1 1--- + --- + --- + --- + .+ ---- = 2x3 3x4 4x5 5x6 9900打不上公式,请见如下描述:1/6 + 7/12 + 1/20 + 1/30 + ......+1/9900 =请问结果是多少?怎么个算法?规律应该是分母分别为 2x3 3x4 4x5 5x6 ..
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式子如下:1 1 1 1 1--- + --- + --- + --- + .+ ---- = 2x3 3x4 4x5 5x6 9900打不上公式,请见如下描述:1/6 + 7/12 + 1/20 + 1/30 + ......+1/9900 =请问结果是多少?怎么个算法?规律应该是分母分别为 2x3 3x4 4x5 5x6 ..
式子如下:
1 1 1 1 1
--- + --- + --- + --- + .+ ---- =
2x3 3x4 4x5 5x6 9900
打不上公式,请见如下描述:
1/6 + 7/12 + 1/20 + 1/30 + ......+1/9900 =
请问结果是多少?怎么个算法?规律应该是分母分别为 2x3 3x4 4x5 5x6 .....99x100
式子如下:1 1 1 1 1--- + --- + --- + --- + .+ ---- = 2x3 3x4 4x5 5x6 9900打不上公式,请见如下描述:1/6 + 7/12 + 1/20 + 1/30 + ......+1/9900 =请问结果是多少?怎么个算法?规律应该是分母分别为 2x3 3x4 4x5 5x6 ..
1/(2*3)+1/(3*4)+1/(4*5)+……+1/(98*99)+1/(99*100)
=(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+……+(1/98-1/99)+(1/99-1/100)
=1/2-1/100
=49/100=0.49
写清楚点
原式=(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+...+(1/99-1/100)
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+...+1/99-1/100
=1/2+(1/3-1/3)+(1/4-1/4)+(1/5-1/5)+(1/6-1/6)...+(1/99-1/99)-1/100
=1/2-1/100
=49/100