WAEC - Further Mathematics (2019 - No. 33)
Which of the following vectors is perpendicular to \(\begin{pmatrix} -1 & 3 \end{pmatrix}\)?
\(\begin{pmatrix} -3 & 1 \end{pmatrix}\)
\(\begin{pmatrix} 1 & 3 \end{pmatrix}\)
\(\begin{pmatrix} 1 & -3 \end{pmatrix}\)
\(\begin{pmatrix} 1 & 3 \end{pmatrix}\)