🛠️ JEE➗ Maths

If \(A=\left(\begin{array}{cc}\frac{1}{\sqrt{5}} & \frac{2}{\sqrt{5}} \\ \frac{-2}{\sqrt{5}} & \frac{1}{\sqrt{5}…

Q1

If \(A=\left(\begin{array}{cc}\frac{1}{\sqrt{5}} & \frac{2}{\sqrt{5}} \\ \frac{-2}{\sqrt{5}} & \frac{1}{\sqrt{5}}\end{array}\right), B=\left(\begin{array}{ll}1 & 0 \\ i & 1\end{array}\right), i =\sqrt{-1}\), and \(Q=A^T B A\), then the inverse of the matrix \(A Q^{2021} A^T\) is equal to

[JEE Main 2021, 26 Aug (Shift 1)]

a

\(
\left(\begin{array}{cc}
1 & 0 \\
2021 i & 1
\end{array}\right)
\)

b

\(
\left(\begin{array}{cc}
\frac{1}{\sqrt{5}} & -2021 \\
2021 & \frac{1}{\sqrt{5}}
\end{array}\right)
\)

c

\(
\left(\begin{array}{cc}
1 & 0 \\
-2021 i & 1
\end{array}\right)
\)

d

\(
\left(\begin{array}{cc}
1 & -2021 i \\
0 & 1
\end{array}\right)
\)

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