a=1,b=2 求1/ab+1/(a+1)(b+1

a=1,b=2 求1/ab+1/(a+1)(b+1)=1/(a+2)(b+20)+...+1/(a+2013)(b+20

1个回答

原式=1/1*2+1/2*3+1/3*4+……+1/2014*2015
=1-1/2+1/2-1/3+1/3-1/4+……+1/2014*2015
=1-1/2015
=2014/2015

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