题目内容
已知a=2+
,b=2-
,则
+
=
| 3 |
| 3 |
| 1 |
| a |
| 1 |
| b |
4
4
.分析:把分式通分计算,然后把a、b的值代入进行计算即可得解.
解答:解:
+
=
=
=
=4.
故答案为:4.
| 1 |
| a |
| 1 |
| b |
=
| a+b |
| ab |
=
2+
| ||||
(2+
|
=
| 4 |
| 4-3 |
=4.
故答案为:4.
点评:本题考查了分母有理化,a、b正好是互为有理化因式是解题的关键.
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