题目内容
求值:(1)2
×
×
;
(2)0.0081
+(4-
)2+(
)-
-16-0.75.
| 3 |
| 3 | 1.5 |
| 6 | 12 |
(2)0.0081
| 1 |
| 4 |
| 3 |
| 4 |
| 8 |
| 4 |
| 3 |
分析:(1)利用根式与分数指数幂的性质,把2
×
×
等价转化为2×3
×(
)
×(3×22)
,由此能够求出结果.
(2)利用根式与分数指数幂的性质,把0.0081
+(4-
)2+(
)-
-16-0.75等价转化为(0.3)4×
+(2-
)2+(2
)-
-24×(-0.75),由此能够求出结果.
| 3 |
| 3 | 1.5 |
| 6 | 12 |
| 1 |
| 2 |
| 3 |
| 2 |
| 1 |
| 3 |
| 1 |
| 6 |
(2)利用根式与分数指数幂的性质,把0.0081
| 1 |
| 4 |
| 3 |
| 4 |
| 8 |
| 4 |
| 3 |
| 1 |
| 4 |
| 3 |
| 2 |
| 3 |
| 2 |
| 4 |
| 3 |
解答:解:(1)原式=2×3
×(
)
×(3×22)
=2×3
×
×3
×2
=2×3=6…(3分)
(2)原式=(0.3)4×
+(2-
)2+(2
)-
-24×(-0.75)
=0.3+2-3+2-2-2-3
=0.3+0.25
=0.55.…(6分)
| 1 |
| 2 |
| 3 |
| 2 |
| 1 |
| 3 |
| 1 |
| 6 |
=2×3
| 1 |
| 2 |
3
| ||
2
|
| 1 |
| 6 |
| 1 |
| 3 |
(2)原式=(0.3)4×
| 1 |
| 4 |
| 3 |
| 2 |
| 3 |
| 2 |
| 4 |
| 3 |
=0.3+2-3+2-2-2-3
=0.3+0.25
=0.55.…(6分)
点评:本题考查根式与分数指数幂的性质,是基础题.解题时要认真审题,仔细解答,注意合理地进行等价转化.
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