题目内容
不用计算器求下列各式的值
(1)(2
)
-(-9.6)0-(3
)-
+(1.5)-2
(2)
•
•
+lg
-3log32.
(1)(2
1 |
4 |
1 |
2 |
3 |
8 |
2 |
3 |
(2)
2 |
3 | 4 |
6 | 32 |
1 |
100 |
分析:(1)化带分数为假分数,化小数为分数,然后利用有理指数幂的运算性质化简求值;
(2)化根式为分数指数幂,然后结合对数的运算性质化简求值.
(2)化根式为分数指数幂,然后结合对数的运算性质化简求值.
解答:解:(1)(2
)
-(-9.6)0-(3
)-
+(1.5)-2
=(
)
-1-(
)-
+(
)-2
=
-1-[(
)3]-
+
=
-1-
+
=
;
(2)
•
•
+lg
-3log32
=2
•2
•2
+lg10-2-2
=2
+
+
-2-2
=4-4=0.
1 |
4 |
1 |
2 |
3 |
8 |
2 |
3 |
=(
9 |
4 |
1 |
2 |
27 |
8 |
2 |
3 |
3 |
2 |
=
3 |
2 |
3 |
2 |
2 |
3 |
4 |
9 |
=
3 |
2 |
4 |
9 |
4 |
9 |
=
1 |
2 |
(2)
2 |
3 | 4 |
6 | 32 |
1 |
100 |
=2
1 |
2 |
2 |
3 |
5 |
6 |
=2
1 |
2 |
2 |
3 |
5 |
6 |
=4-4=0.
点评:本题考查了有理指数幂的化简与求值,考查了对数的运算性质,关键是熟记有关性质,是基础的计算题.
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