(a-1)+/ab-2/=0,求1/ab+1/(a+1)(b+1)+...7/(a+2007)(b+2007)的值
问题描述：
(a-1)+/ab-2/=0,求1/ab+1/(a+1)(b+1)+...7/(a+2007)(b+2007)的值
答
(a-1)^2+/ab-2/=0
a=1 ab-2=0
a=1 b=2
1/ab+1/(a+1)(b+1)+...1/(a+2007)(b+2007)
=1/1*2 +1/2*3 +.1/2008*2009
=1-1/2 +1/2-1/3+.1/2008-1/2009
=1-1/2009
=2008/2009