题目内容
计算下列各式的值:
(1)0.064-
-(-
)0+16
+0.25
;
(2)log216+2log36-log312+log31.
(1)0.064-
1 |
3 |
1 |
8 |
3 |
4 |
1 |
2 |
(2)log216+2log36-log312+log31.
分析:(1)先利用有理指数幂进行化简,最后通分计算;
(2)直接利用对数式的运算性质化简求值.
(2)直接利用对数式的运算性质化简求值.
解答:解:(1)0.064-
-(-
)0+16
+0.25
=(0.43)-
-1+(24)
+(0.52)
=0.4-1-1+8+
=
-1+8+
=10;
(2)log216+2log36-log312+log31
=4+log336-log312+0
=4+log33+0
=4.
1 |
3 |
1 |
8 |
3 |
4 |
1 |
2 |
=(0.43)-
1 |
3 |
3 |
4 |
1 |
2 |
=0.4-1-1+8+
1 |
2 |
=
5 |
2 |
1 |
2 |
(2)log216+2log36-log312+log31
=4+log336-log312+0
=4+log33+0
=4.
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,解答的关键是熟记有关性质,是基础题.

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