title: How to type tilde in formulas in RMarkdown
body: <p>I am trying to type equations on RMarkdown to create a PDF and I want to use a tilde, how can I go about it. I am trying this but throws back a <code>pandoc.exe: Error producing PDF from TeX source ....</code></p>
  
  <pre><code>---
  title: "See"
  date: "24 September 2016"
  output: html_document
  ---
  
  ```{r setup, include=FALSE}
  knitr::opts_chunk$set(echo = TRUE)
  ```
  
  follows a Bernouli distribution 
  $$y_i \~ Bernouli(p_i)$$
  </code></pre>