multicolumn in array environment

Question

I want to create a matrix like the following in a math environment but i keep getting compile errors.

\begin{array}{c c c c}
\multicolumn{3}{c}{R} & P \\
0 & 0 & 0 & 1
\end{array}

Answer 1

The following runs without errors:

\documentclass{article}
\begin{document}
\[
\begin{array}{c c c c}
\multicolumn{3}{c}{R} & P \\
0 & 0 & 0 & 1
\end{array}
\]
\end{document}