WAEC - Further Mathematics (2020 - No. 2)
Find the inverse of \(\begin{pmatrix} 3 & 5 \\ 1 & 2 \end{pmatrix}\)
\(\begin{pmatrix} 5 & 1 \\ -3 & 2 \end{pmatrix}\)
\(\begin{pmatrix} 2 & -5 \\ -1 & 3 \end{pmatrix}\)
\(\begin{pmatrix} -5 & 2 \\ -1 & 3 \end{pmatrix}\)
\(\begin{pmatrix} 5 & 1 \\ 2 & 3 \end{pmatrix}\)
설명
Let A = \(\begin{pmatrix} 3 & 5 \\ 1 & 2 \end{pmatrix}\)
|A| = (3 x 2 - 5 x 1)
= 6 - 5
= 1
A\(^{-1}\) = \(\begin{pmatrix} 2 & -5 \\ -1 & 3 \end{pmatrix}\)