MCQ
For matrix $A =\left[\begin{array}{lll}2 & 0 & 0 \\ 0 & 3 & 0 \\ 0 & 0 & 4\end{array}\right],\left( A ^{-1}\right)^2=$ __________ .
  • A
    $\left[\begin{array}{ccc}-\frac{1}{4} & 0 & 0 \\ 0 & -\frac{1}{9} & 0 \\ 0 & 0 & -\frac{1}{16}\end{array}\right]$
  • B
    $\left[\begin{array}{ccc}-4 & 0 & 0 \\ 0 & -9 & 0 \\ 0 & 0 & -16\end{array}\right]$
  • $\left[\begin{array}{ccc}\frac{1}{4} & 0 & 0 \\ 0 & \frac{1}{9} & 0 \\ 0 & 0 & \frac{1}{16}\end{array}\right]$
  • D
    $\left[\begin{array}{ccc}4 & 0 & 0 \\ 0 & 9 & 0 \\ 0 & 0 & 16\end{array}\right]$

Answer

Correct option: C.
$\left[\begin{array}{ccc}\frac{1}{4} & 0 & 0 \\ 0 & \frac{1}{9} & 0 \\ 0 & 0 & \frac{1}{16}\end{array}\right]$
C

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