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因为b+a/ab=b/ab+a/ab=1/a+1/b,所以原题可裂项为:
8/3*5+12/5*7-16/7*9+20/9*11-...-4032/2015*2017
=8/15+5+7/5*7-7+9/7*9+...-2015+2017/2015*2017
=8/15+(1/5+1/7)-(1/7+1/9)+(1/9+1/11)-...+(1/2013+1/2015)-(1/2015+1/2017)
=8/15+1/5+1/7-1/7-1/9+1/9-...+1/2013+1/2015-1/2015-1/2017
=8/15+1/5-1/2017
=11/15-1/2017
=22172/30255
8/3*5+12/5*7-16/7*9+20/9*11-...-4032/2015*2017
=8/15+5+7/5*7-7+9/7*9+...-2015+2017/2015*2017
=8/15+(1/5+1/7)-(1/7+1/9)+(1/9+1/11)-...+(1/2013+1/2015)-(1/2015+1/2017)
=8/15+1/5+1/7-1/7-1/9+1/9-...+1/2013+1/2015-1/2015-1/2017
=8/15+1/5-1/2017
=11/15-1/2017
=22172/30255
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