因为√a-1≥0 (ab-2)的平方≥0而√a-1+(ab-2)的平方=0所以√a-1=0 (ab-2)的平方=0a=1 b=2原式=1/(1*2)+1/(2*3)+1/(3*4)+..................1/(2005*2006) =1-1/2+1/2-1/3+1/3-1/4+1/4-.................+1/2005-1/2006 =1-1/2006 =2005/2006希望采纳