|ab+2|+|a+1|=0
a+1=0 a=-1
ab=-2 b=-2/a=2
(a-1)(b+1)分之一+(a-2)(b+2)分之一+---+(a-2004)(b+2004)
=-1/2x3-1/3x4-...-1/2005x2006
=-(1/2x3+1/3x4+...+1/2005x2006)
=-(1/2-1/3+1/3-1/4+...+1/2005-1/2006)
=-(1/2-1/2006)
=-(1003/2006-1/2006)
=-501/1003
|ab+2|+|a+1|=0
a+1=0 a=-1
ab=-2 b=-2/a=2
(a-1)(b+1)分之一+(a-2)(b+2)分之一+---+(a-2004)(b+2004)
=-1/2x3-1/3x4-...-1/2005x2006
=-(1/2x3+1/3x4+...+1/2005x2006)
=-(1/2-1/3+1/3-1/4+...+1/2005-1/2006)
=-(1/2-1/2006)
=-(1003/2006-1/2006)
=-501/1003