计算(1/2+1/3+...+1/2011)(1+1/2+1/3+...+1/2010)-(1+1/2+...1/2011)(1/2+1/3+...+1/2010) .

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计算(1/2+1/3+...+1/2011)(1+1/2+1/3+...+1/2010)-(1+1/2+...1/2011)(1/2+1/3+...+1/2010) .
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计算(1/2+1/3+...+1/2011)(1+1/2+1/3+...+1/2010)-(1+1/2+...1/2011)(1/2+1/3+...+1/2010) .
计算(1/2+1/3+...+1/2011)(1+1/2+1/3+...+1/2010)-(1+1/2+...1/2011)(1/2+1/3+...+1/2010) .

计算(1/2+1/3+...+1/2011)(1+1/2+1/3+...+1/2010)-(1+1/2+...1/2011)(1/2+1/3+...+1/2010) .
设a= 1+1/2+...1/2011
(1/2+1/3+...+1/2011)(1+1/2+1/3+...+1/2010)-(1+1/2+...1/2011)(1/2+1/3+...+1/2010)
=(a-1)(a-1/2011)-a(a-1-1/2011)
=1/2011

0

(1/2+1/3+...+1/2011)(1+1/2+1/3+...+1/2010)-(1+1/2+...1/2011)(1/2+1/3+...+1/2010)
=(1/2+1/3+....1/2011)+(1/2+1/3+1/4+.....1/2011)(1/2+......1/2010)-(1+1/2+...1/2011)(1/2+1/3+...+1/2010)
=(1/2+1...

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(1/2+1/3+...+1/2011)(1+1/2+1/3+...+1/2010)-(1+1/2+...1/2011)(1/2+1/3+...+1/2010)
=(1/2+1/3+....1/2011)+(1/2+1/3+1/4+.....1/2011)(1/2+......1/2010)-(1+1/2+...1/2011)(1/2+1/3+...+1/2010)
=(1/2+1/3+....1/2011)+(1/2+1/3+1/4+.....1/2010)【(1/2+......1/2011)-(1+1/2+...1/2011)】
=(1/2+1/3+....1/2011)-(1/2+1/3+1/4+.....1/2010)
=1/2011

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