## 等价无穷小 `$ sin x \sim x $` `$ arcsinx \sim x \sim arctanx $` `$ ln(1+x) \sim x $` `$ e^x -1 \sim x $` `$ tan x \sim x $` `$ 1-cosx \sim \frac {x^2} {2} $` `$ (1+x)^\mu -1 \sim \mu x $` `$ \sqrt[n]{1+x} \sim \frac x n $` `$ a^x -a \sim x \ln a $` ##　重要极限 ```[math] \lim_{x\rightarrow 0 } \frac {sin x} x = 1 ``` ```[math] \lim_{x\rightarrow \infin}(1 + \frac 1 x)^x = e ``` ```[math] ``` ```[math] ``` ```[math] ``` ```[math] ``` `$ $` `$ $` `$ $` `$ $` `$ $` `$ $` `$ $` `$ $` `$ $` `$ $` `$ $` `$ $` `$ $` `$ $` ```[math] \lim_{xida\rightarrow 0 } \frac {tan (xida)} {xida} = 1 ```