I have the following code:
\begin{table}[h]
\begin{tabularx}{\textwidth}{ m{4cm} X }
& Derivations \\
$v=v_0+at$ & test \newline test \newline test \\
$x=x_0+v_0t+½at^2$ & a\\
$v^2-v_0^2=2a(x-x_0)$ & a\\
$x-x_0=½t(v_0-v)$ & a
\end{tabularx}
\end{table}
The m{4cm} will make a 4cm wide column with vertically centered content according to this answer to another question. I have added the array package. But no vertical centering happens; the result is:

How can I make the content in the left column (which consists of $..$ equations) vertically align to the center.



mis happening. It makes the reference point of the first column its vertical centre rather than its baseline, and that reference point aligns with the reference point of the second column which is the baseline of its top row. – David Carlisle May 01 '15 at 16:02