The first test case is to create a matrix consisting of following elements $$ \begin{matrix} 1 & x & x^2 \ 1 & y & y^2 \ 1 & z & z^2 \ \end{matrix} $$

but all elemments of the matrix are displayed in one line. Fortunately, this can be solved by wraping the math expression inside a <div> </div> block, which is hinted by the hugo documents of MathJax Support. besides, the blank line before <div> </div> block is necessary, otherwise the matrix would not be displayed correctly.

Actually, what I would like to do is to display multi-line equations. Taking the example from the stackoverflow question [Mathjax multi-line equation rendering issue] ( http://stackoverflow.com/questions/18860693/mathjax-multi-line-equation-rendering-issue), I input following MathJax expressions.

$$
\begin{eqnarray} 
y &=& x^4 + 4      \nonumber \\
  &=& (x^2+2)^2 -4x^2 \nonumber \\
  &\le&(x^2+2)^2    \nonumber
\end{eqnarray} 
$$

$$ \begin{eqnarray} y &=& x^4 + 4 \nonumber \ &=& (x^2+2)^2 -4x^2 \nonumber \ &\le&(x^2+2)^2 \nonumber \end{eqnarray} $$

As you can see, the equations are displayed in one line. From the comments of the question, the solution is to use \\\\\\ instead of \\ as newline command, which also can be applied to the test example of matrix. But I think typing 6 \ is quite tedious. Is there any concise solution?

$$ \begin{eqnarray} y &=& x^4 + 4 \nonumber \\\ &=& (x^2+2)^2 -4x^2 \nonumber \\\ &\le&(x^2+2)^2 \nonumber \end{eqnarray} $$

Alternative way to display matrix correctly is to use \\\\\\ instead of \\ as newline command. $$ \begin{matrix} 1 & x & x^2 \\\ 1 & y & y^2 \\\ 1 & z & z^2 \\\ \end{matrix} $$