If P = \(\begin{pmatrix} 2 & -3 \\ 1 & 1 \end{pmatrix}\) , what is P\(^-1\)
A
\(\begin{pmatrix} -{\frac{1}{5}} & -{\frac{3}{5}} \\ -{\frac{1}{5}} & -{\frac{2}{5}} \end{pmatrix}\)
B
\(\begin{pmatrix} {\frac{1}{5}} & {\frac{3}{5}} \\ {\frac{1}{5}} & {\frac{2}{5}} \end{pmatrix}\)
C
\(\begin{pmatrix} -{\frac{1}{5}} & {\frac{3}{5}} \\ -{\frac{1}{5}} & {\frac{2}{5}} \end{pmatrix}\)
D
\(\begin{pmatrix} {\frac{1}{5}} & {\frac{3}{5}} \\ -{\frac{1}{5}} & {\frac{2}{5}} \end{pmatrix}\)
Verified Correct Answer: D.
Step-by-Step Mathematical Solution
P = \(\begin{pmatrix} 2 & -3 \\ 1 & 1 \end{pmatrix}\)
|P| = 2 - 1 x -3 = 5
P-1 = \(\frac{1}{5}\)\(\begin{pmatrix} 1 & 3 \\ -1 & 2 \end{pmatrix}\)
= \(\begin{pmatrix} {\frac{1}{5}} & {\frac{3}{5}} \\ -{\frac{1}{5}} & {\frac{2}{5}} \end{pmatrix}\)
Source: WAEC / JAMB / NECO Classroom Archive (Record #29576)