题目内容
(1)求值:lg52+
lg8+lg5•lg20+(lg2)2
(2)求值:(0.0081)-
-[3×(
)0]-1×[81-0.25+(3
)-
]-
-10×0.027
.
2 |
3 |
(2)求值:(0.0081)-
1 |
4 |
7 |
8 |
3 |
8 |
1 |
3 |
1 |
2 |
1 |
3 |
(1)lg52+
lg8+lg5•lg20+(lg2)2
=2lg5+
lg23+lg5(1+lg2)+(lg2)2
=2lg5+2lg2+lg5(1+lg2)+(lg2)2
=2(lg5+lg2)+lg5+lg5•lg2+(lg2)2
=2+lg5+lg2(lg5+lg2)=3.
(2)(0.0081)-
-[3×(
)0]-1×[81-0.25+(3
)-
]-
-10×0.027
=((0.3)4)-
-3-1×[(34)-
+(
)-1]-
-10×((0.3)3)
=
-
(
+
)-
-10•0.3
=
-
-3
=0.
2 |
3 |
=2lg5+
2 |
3 |
=2lg5+2lg2+lg5(1+lg2)+(lg2)2
=2(lg5+lg2)+lg5+lg5•lg2+(lg2)2
=2+lg5+lg2(lg5+lg2)=3.
(2)(0.0081)-
1 |
4 |
7 |
8 |
3 |
8 |
1 |
3 |
1 |
2 |
1 |
3 |
=((0.3)4)-
1 |
4 |
1 |
4 |
3 |
2 |
1 |
2 |
1 |
3 |
=
10 |
3 |
1 |
3 |
1 |
3 |
2 |
3 |
1 |
2 |
=
10 |
3 |
1 |
3 |
=0.
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