题目内容
先简化，再求值：(1+
)÷(x-
)×
，其中x=
+1．
| 1 |
| x2-1 |
| x |
| x+1 |
| 125 |
| 5 |
原式=(
+
)÷[
-
]×5
=
•
•5
=
，
将x=
+1代入上式，得
=
=5．
| x2-1 |
| x2-1 |
| 1 |
| x2-1 |
| x(x+1) |
| x+1 |
| x |
| x+1 |
| 5 |
=
| x2 |
| x2-1 |
| x+1 |
| x2 |
| 5 |
5
| ||
| x-1 |
将x=
| 5 |
5
| ||
| x-1 |
5
| ||
|
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