超难的初中数学题!!!!!

来源:百度知道 编辑:UC知道 时间:2024/05/04 18:38:22
(1)填空:(1/a)-(1/a+1)=( )
(1/a+1)-(1/a+2)=
(1/a+n)-(1/a+n+1)=
(2)计算:[1/a(a+1)]+[1/(a+1)(a+2)]+[1/(a+2)(a+3)]+......+[1/(a+2007)(a+2008)]
=
要过程!!!完整的还有追加!!!

1、(1)原式=1/a(a+1)
(2)原式=1/(a+1)(a+2)
(3)原式=1/(a+n)(a+n+1)
2、原式=(1/a)-(1/a+1)+(1/a+1)-(1/a+2)+(1/a+2)-(1/a+3)+(1/a+3)-.......+1/(a+2007)-1/(a+2008)
=1/a-1/(a+2008)
=2008/a(a+2008)

填空1.1/(a(a+1))
2.1/((a+1)(a+2))
3.1/((a+n)(a+n+1))
计算原式=1/a-1/(a+1)+1/(a+1)-1/(a+2)+1/(a+2)-1/(a+3)+……+1/(a+2006)-1/(a+2007)+1/(a+2007)-1/(a+2008)=1/a-1/(a+2008)

(1)
1. -1
2. -1
3. -1
(你只需记住去括号时要变号,就解出来了`)

(2)你把‘×’写成‘+’了吧```看看写的对不对?