Here's the question you clicked on:
UnkleRhaukus
\[\begin{array}{|c|c|c|c|c|}\hline \phi&\psi&\phi\Rightarrow\psi&\phi \Leftarrow\psi&\phi\Leftrightarrow\psi\\ \hline T&T&T&T&T\\T&F&F&T&F\\F&T&T&F&F\\F&F&T&T&T\\ \hline\end{array}\]
how come that horizontal line is continuing outside the array, this isn's a problem when i use TeXShop, ?
\[\rm TeXShop \ne MathJax\]