第1个回答 2008-04-14
2a^2+4ab+5b^2+4a-2b+5=(a^2+4ab+4b^2)+(a^2+4a+4)+(b^2-2b+1)=(a+2b)^2+(a+2)^2+(b-1)^2=0
a=-2b a=-2 b=1
1/ab+1/(a-1)(b+1)+1/(a-2)(b+2)+...+1/(a-2007)(b+2007)=1/(-2*1)+1/(-3*2)+...+1/(-2009*2008)=-1+1/(2)-1/2+1/(3)+...-1/(2008)+1/(2009)=-1-1/2009=2010/2009
好怀恋这样的题目.... 初三做滥了的.....