|ab-2|>=0
(b-1)^2>=0
|ab-2|与(b-1)^2互为相反数
则
|ab-2|=(b-1)^2=0
ab-2=0
b-1=0
a=2
b=1
1/ab+1/(a+1)(b+1)+1/(a+2)(b+2)+...1/(a+2006)(b+2006)
=1/2*1+1`/(2+1)(1+1)+1/(2+2)(1+2)+.+1/(2+2006)(1+2006)
=1/1*2+1/2*3+1/3*4+.+1/2007*2008
=1-1/2+1/2-1/3+1/3-1/4+.+1/2007-1/2008
=1-1/2008
=2007/2008