53 lines
945 B
Markdown
53 lines
945 B
Markdown
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---
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title: Basic Log Rules and Expanding Log Expressions
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localeTitle: 基本日志规则和扩展日志表达式
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---
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## 基本日志规则和扩展日志表达式
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以下是常用的基本日志规则:
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###### 对数乘积规则
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log b (x \* y)= log b (x)+ log b (y)
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###### 对数商数规则
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log b (x / y)= log b (x) - log b (y)
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###### 对数幂规则
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log b (x y )= y \* log b (x)
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###### 负数的对数
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当x <0时, log b (x)未定义
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###### 对数为0
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log b (0)未定义
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lim x→0+ log b (x)= -infinity
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###### 对数为1
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log b (1)= 0
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###### 基数的对数
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log b (b)= 1
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###### 无限的对数
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lim x→无穷远 log b (x)=无穷大
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###### 对数基本切换规则
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log b (c)= 1 / log c (b)
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###### 对数基数变化规则
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log b (x)= log c (x)/ log c (b)
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#### 更多信息:
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[对数规则](http://www.rapidtables.com/math/algebra/Logarithm.htm)
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