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20
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20
?20????????????1.072??
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x
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(1)???logaN????????????x???????? (2)???????????????????????? ???a?N???????????a?x?N????????????????a?x??N??????????????x????????N??a?????????????
?a???a,N???x???????????????logaN= x?????????????????????????????????????????????????????????logaN?????a??N????????????????????
???????????????????????????? ????????logaN?a?0?a?1????a=10????????(common logarithm)???lgN???a=e????????(natural logarithm)???lnN???e???????e?2.718 28???
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x
x
1?1?
(1)5
?625;(2)2?;(3)???5.73
64?3?
4
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m
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2
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2
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x
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2
35
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log24
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2
2
log327lg105
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logN
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3
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(m,n?Z)?(am)n?amn (m,n?Z)?(ab)n?an?bn (n?Z)?
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pq
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?????????????????????????????????? ?????????????log2?3264?=? ??log2?3264?=log232+log264=5+6=11?
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m
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481
4. ??????????? ? ??????????N?0? ? 1????0??loga1?0? ? ??????1??logaa?1?
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x
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(1) 54=625 (2) 2?6?
1
164
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3
2
(7) lg0.01??2(8) ln10?2.303
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1
164
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3
2
(5) 10?2?0.01(6) e2.303?10
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23
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23
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3
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23
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1
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log
x
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6
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x
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x
1
2
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lg100?x????10?lne
2
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2
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2
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2
,??x??2
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x
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a
N
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发表于 2019-9-13 23:46:11