题目内容
先化简,再求值:(
+
)÷
,其中x=2+
.
x+2 |
x-2 |
4 |
x2-4x+4 |
x |
x-2 |
2 |
原式=[
+
]•
=
•
=
,
当x=2+
时,原式=
=
=
+1.
x+2 |
x-2 |
4 |
(x-2)2 |
x-2 |
x |
=
x2 |
(x-2)2 |
x-2 |
x |
=
x |
x-2 |
当x=2+
2 |
2+
| ||
2+
|
2
| ||
2 |
2 |
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