weng007008
幼苗
共回答了32个问题 举报
因已知(a-1)的平方+ab-2的绝对值=0,所以a-1=0,a=1;ab-2的绝对值=0,ab=2,b=2
1/ab+1/(a+1)*(b+1)+1/(a+2)*(b+2)+…+1/(a+2009)*(b+2009)+1/(a+2010)*(b+2010)
=1/2+1/(2*3)+1/(3*4)+......+1/(2010*2011)+1/(2011*2012)
=1/2+1/2-1/3+1/3-1/4+......+1/2010-1/2011+1/2011-1/2012
=1-1/2012
=2011/2012
1年前
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