Question

请帮忙解下题已知|ab-2|与|b-1|互为相反数,试求代数式.1/ab+1/(a+1)(b+1)+1/(a+2)(b+

Answer 1

已知|ab-2|与|b-1|互为相反数,

b-1=0 b=1

ab-2=0 a=2

1/ab+1/(a+1)(b+1)+1/(a+2)(b+2)+.+1/(a+2004)(b+2004)

=1/1x2+1/2x3+1/3x4+……+1/2005x2006

=1-1/2+1/2-1/3+1/3-1/4+……+1/2005-1/2006

=1-1/2006

=2005/2006