1/1x4+1/4x7+1/7x10+...+1/73x76=? 急啊······

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1/1x4+1/4x7+1/7x10+...+1/73x76=?急啊······1/1x4+1/4x7+1/7x10+...+1/73x76=?急啊······1/1x4+1/4x7+1/7x10+.

1/1x4+1/4x7+1/7x10+...+1/73x76=? 急啊······
1/1x4+1/4x7+1/7x10+...+1/73x76=? 急啊······

1/1x4+1/4x7+1/7x10+...+1/73x76=? 急啊······
1/1x4+1/4x7+1/7x10+...+1/73x76
=1/3(1-1/4+1/4-1/7+...+1/73-1/76)
=1/3*75/76
=25/76

1/a*(a+3)然后a从1到73
 double d=0.0;
 for(int i=1;i<=73;i+=3){
 d+=new Double(1.0)/new Double(i)*new Double((i+3));
 System.out.println(d);
 }
 System.out.println(d);

答案是31.344288162105848

证明很简单.. 若x是实数,不是整数,设x的小数部分为k,整数部分x-k=m, 则左侧为[(m-1) k][(m-2) k][(m-3) k][(m-4) k]=整数 k*

100x( 3/1x4 + 3/4x7 +3/7x10 +.3/97x100)=?注：1x4、4x7、7x10等均为分母的大小 1/1x4+1/4x7+1/7x10+1/10x13+1/13X16 简便 计算：1/（1x4）+1/（4x7）+1/(7x10)…+1/(298x301) 计算1/1x4+1/4x7+1/7x10+***+1/2007x2010 1/1x4+1/4x7+1/7x10+……+1/2005x2008佼佼我 1/1X4+1/4X7+1/7X10+...+1/100X103= 1/1x4+1/4x7+1/7x10+……+1/97x100SOS!SOS! 1/(1x4)+1/(4x7)+1/(7x10)+...+1/(91x94) 1/1X4+1/4X7+1/7X10+.+1/2002X2005=?有规律的 1/1x4+1/4x7+1/7x10+……+1/2005x2008 1X4/1+4X7/1+7X10/1+…+2005X2008/1=? 1/1x4 +1/4x7+1/7x10+.+1/100x103 急用啊 小学分数题：1/1x4+1/4x7+1/7x10+.+1/97x100 1/1x4 + 1/4x7 + 1/7x10 +…+ 1/91x94=? 1X4/1+4X7/1+7X10/1+…+2005X2008/1=? 计算 1X4分之一+4x7分之一+7x10分之一+...+2008x2011分之一的值 3/(1X4)+3/(4X7)+3/(7X10)+3/(10X13)+3/(13X16) 计算1/1X4+1X7+ 1/7x10+...+1/2008X2011的值是多少