zhoubingbing2004
幼苗
共回答了21个问题采纳率:90.5% 举报
1乘2分之X+2乘3分之X+...+2010乘2011分之X=2010 ==> x(1-1/2) + x*(1/2 - 1/3) + ...+ x (1/2010 - 1/2011) = 2010 ==> x ( 1 - 1/2 + 1/2 + 1/3 + ...+ 1/2010 - 1/2011) = 2010 ==> x ( 1 - 1/2011) = 2010 ==> x (2010 / 2011) = 2010 ==> x / 2011 = 1 ==> x = 2011
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