题目内容
已知,a=| 1 | ||
|
| 1 | ||
|
| b |
| a |
| a |
| b |
分析:先计算出ab=
,a+b=
,然后把式子
+
化为
=
,把它们的值代入即可.
| 1 |
| 2 |
| 3 |
| b |
| a |
| a |
| b |
| b2+a2 |
| ab |
| (a+b)2-2ab |
| ab |
解答:解:
+
=
,
=
,
=
,
=4.
故答案为:4.
| b |
| a |
| a |
| b |
| b2+a2 |
| ab |
=
| (a+b)2-2ab |
| ab |
=
| 3-1 | ||
|
=4.
故答案为:4.
点评:本题考查了二次根式的混合运算,要掌握好运算顺序及各运算律.
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