title: matrix by matrix in R markdown
body: <p>I want to have multiple matrices side by side to present spectral decomposition in R markdown, but it doesn't seem to work. Please help </p>
  
  <pre><code>$$
  \left(\begin{array}
  0.8944272 &amp; 0.4472136\\
  -0.4472136 &amp; -0.8944272
  \end{array}\right\)
  
  \left(\begin{array}
  10 &amp; 0\\
  0 &amp; 5
  \end{array}\right)
  $$ 
  </code></pre>