github pages - My website based on Jekyll does not work with MathJax -

my problem

so can have on problem, see blog post in link: https://matheusrabetti.github.io/statistics/bayesian-introduction/

in end of post can see - "this can represented beta distribution parameters , ( \beta=219):"

here markdown file have code: this can represented beta distribution parameters $$\alpha=81$$ , \( \beta=219\):

i expecting see tex formula, when using $$, on website , it's returning blank space.

my path until know

in _includes folder - check github repository here https://github.com/matheusrabetti/matheusrabetti.github.io - have following code in _scripts.html file:

<script type="text/x-mathjax-config"> mathjax.hub.config({     tex2jax: {   inlinemath: [['$','$'], ['\\(','\\)']],   displaymath: [ ['$$','$$'], ['\\[','\\]'] ],   processescapes: true      } }); </script>  <script type="text/javascript"    src="http://cdn.mathjax.org/mathjax/latest/mathjax.js?config=tex-ams-mml_htmlormml"> </script>  

this javacript code has been in _header.html , many other files.

i'm using interpreter:

markdown: kramdown

my _layout posts files including _scripts.html:

{% include _scripts.html %}  </body> </html> 

where page blank, inspecting html page found that:

the mean <script type="math/tex">   \frac{\alpha}{\alpha + \beta} = \frac{81}{81+219} = 0.270 <\script> 

as can see have little knowledge on jekyll or octopress , give more informations comes, because don't know what's problem , can you.