初一数学题已知A乘B
已知A乘B-2的绝对值和B-1的绝对值互为相反数,试求 1/AB+1/(A+1)乘(B+1)......+1/(A+2005)乘(B+2005)的值
|AB-2|=-|B-1|,B=1,A=2 1/(1*2)+1/(2*3)+1/(3*4)+...+1/(2006*2007) =1/1-1/2+1/2-1/3+1/3-1/4+....+1/2006-1/2007 =1-1/2007=2006/2007