Mathematics · 2018
JEE Main · 15 April 2018, Shift 1 · Q64
Let A be a matrix such that A · [1, 2; 0, 3] is a scalar matrix and |3 A |=108. Then A^2 equals:
Let A be a matrix such that $\displaystyle \mathrm{A} \cdot\left[\begin{array}{ll}1 & 2 \\ 0 & 3\end{array}\right]$ is a scalar matrix and $\displaystyle |3 \mathrm{~A}|=108$. Then $\displaystyle \mathrm{A}^2$ equals :
Official answer
(4)
$\displaystyle \left[\begin{array}{rr}
36 & -32 \\
0 & 4
\end{array}\right]$
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JEE Main 2018 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.