题目内容
计算:
(1)(π)0+(2
)0.5+0.1-2+(2
) -
+
;
(2)
lg
-
lg
+lg
.
(1)(π)0+(2
7 |
9 |
10 |
27 |
2 |
3 |
37 |
48 |
(2)
1 |
2 |
32 |
49 |
4 |
3 |
8 |
245 |
考点:对数的运算性质
专题:计算题,函数的性质及应用
分析:(1)(π)0=1,2
=
,2
=
,代入化简解得;
(2)利用指数运算及对数运算法则运算.
7 |
9 |
25 |
9 |
10 |
27 |
64 |
27 |
(2)利用指数运算及对数运算法则运算.
解答:
解:(1)(π)0+(2
)0.5+0.1-2+(2
) -
+
=1+(
)2×0.5+
+(
)3×(-
)+
=1+
+100+
+
=101+3=104;
(2)
lg
-
lg
+lg
=
lg32-
lg49-
×
lg8+
lg245
=
lg2-lg7-2lg2+
lg245
=
lg2+
lg245-lg7
=
lg490-lg7
=lg7+
-lg7
=
.
7 |
9 |
10 |
27 |
2 |
3 |
37 |
48 |
=1+(
5 |
3 |
1 |
0.12 |
4 |
3 |
2 |
3 |
37 |
48 |
=1+
5 |
3 |
9 |
16 |
37 |
48 |
=101+3=104;
(2)
1 |
2 |
32 |
49 |
4 |
3 |
8 |
245 |
=
1 |
2 |
1 |
2 |
4 |
3 |
1 |
2 |
1 |
2 |
=
5 |
2 |
1 |
2 |
=
1 |
2 |
1 |
2 |
=
1 |
2 |
=lg7+
1 |
2 |
=
1 |
2 |
点评:本题考查了指数与对数运算,属于中档题.
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