title: How to support latex in GitHub-pages?
body: <p>I use jekyll to write post and show it in GitHub-pages. My source file is written with markdown.</p>
  <p>How can I insert formula into the markdown file?</p>
  <p><strong>I don't want to save the formula into an image and load the image in markdown file.</strong> I actually want to write latex formula in markdown file directly.</p>