已知│ab+2│+│a+1 │=0,求式[1/(a-1)(b+1)]+[1/(a-2)(b+2)]+……+[1/(a-2004)(b+2004)]的值

熱心網友

因為│ab+2│,│a+1 │分別都大于等于0,且他們的和等于0所以│ab+2│,│a+1 │等于0所以a=-1,b=2所以所求式可化為:1/(-2)*3+1/(-3)*4......+1/(-2005)*2006=-1/2+1/3-1/3+1/4+......-1/2005+1/2006=-1/2+1/2006=-501/1003