Markdown class Git inserting formula

  Recently I want to add in the code submitted by the formula described, but the git's comment is not directly edit box enter the formula, and the Internet to find under the relevant solutions, is better GitHub Markdown files into the formula method , according to the author's introduction method, only need to enter the following link in the edit box:

 ![](http://latex.codecogs.com/gif.latex?\\sigma=\sqrt{\frac{1}{n}{\sum_{k=1}^n(x_i-\bar{x})^2}})

  That input mode to:

![](https://latex.codecogs.com/gif.latex?公式内容)

  The authors noted:

Note To double backslash \\to escape

  This is not quite understand, in particular, found a formula involving multiple rows or rows matrix needs to be replaced, the result is not displayed. So my approach is:

• Enter the formula may CodeCogs Equation Editor test on;
• Currently found align*multiple lines under the not take effect, so a one per line link to solve;
• For the determination condition cases, the wrap is effective, it needs to \\be replaced \\\\.

  For example:

![](https://latex.codecogs.com/gif.latex?T_{new}=\begin{cases}T_{old}&T_{Input}<T_{Threshold}\\\\T_{Input}&other\end{cases})