题目内容
解答下列各题:
(1)计算:(1-2
)0-2-2-|-3|+sin30°;
(2)先化简,再求值:
-
÷(a+1),其中a=
+2.
(1)计算:(1-2
| 3 |
(2)先化简,再求值:
| a2+a-3 |
| a-2 |
| a2+2a+1 |
| a-2 |
| 2 |
(1)原式=1-
-3+
=-
;
(2)原式=
-
•
=
=
=a+2,
当a=
+2时,原式=
+4.
| 1 |
| 4 |
| 1 |
| 2 |
| 7 |
| 4 |
(2)原式=
| a2+a-3 |
| a-2 |
| (a+1)2 |
| a-2 |
| 1 |
| a+1 |
=
| a2+a-3-a-1 |
| a-2 |
=
| (a+2)(a-2) |
| a-2 |
当a=
| 2 |
| 2 |
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