题目内容
计算下列各式:(1)(2
| 1 |
| 4 |
| 1 |
| 2 |
| 3 |
| 8 |
| 2 |
| 3 |
(2)log3
| |||
| 3 |
分析:(1)将各项的底数化为幂的形式,利用指数的运算法则求解即可.
(2)将
化为3的分数指数幂形式,将lg25+lg4利用对数的运算法则化为lg100=2,7log72由对数的意义知为2,结果可求出.
(2)将
| |||
| 3 |
解答:解:(1)原式=(
)
-1-(
)-
+(
)-2
=(
)2×
-1-(
)-3×
+(
)-2
=
-1-(
)-2+(
)-2=
(2)原式=log3
+lg(25×4)+2
=log33-
+lg102+2
=-
+2+2=
| 9 |
| 4 |
| 1 |
| 2 |
| 27 |
| 8 |
| 2 |
| 3 |
| 3 |
| 2 |
=(
| 3 |
| 2 |
| 1 |
| 2 |
| 3 |
| 2 |
| 2 |
| 3 |
| 3 |
| 2 |
=
| 3 |
| 2 |
| 3 |
| 2 |
| 3 |
| 2 |
| 1 |
| 2 |
(2)原式=log3
3
| ||
| 3 |
=log33-
| 1 |
| 4 |
=-
| 1 |
| 4 |
| 15 |
| 4 |
点评:本题考查指数和对数的运算法则、根式和分数指数幂的互化、对数恒等式等知识,考查运算能力.
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