(a-1)2+|ab-2|=0
所以a-1=0,ab-2=0
a=1,b=2/a=2
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=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

没看懂1/n(n+1)=1/n-1/(n+1)
采纳吧