MCQ
If $A = \left[ {\begin{array}{*{20}{c}}2&0&0\\0&2&0\\0&0&2\end{array}} \right],$then ${A^5} = $
  • A
    $5A$
  • B
    $10A$
  • $16A$
  • D
    $32A$

Answer

Correct option: C.
$16A$
c
(c) $A = \left[ {\begin{array}{*{20}{c}}2&0&0\\0&2&0\\0&0&2\end{array}} \right]\, \Rightarrow {A^5} = \left[ {\begin{array}{*{20}{c}}{{2^5}}&0&0\\0&{{2^5}}&0\\0&0&{{2^5}}\end{array}} \right] = {2^4}\left[ {\begin{array}{*{20}{c}}2&0&0\\0&2&0\\0&0&2\end{array}} \right]$
$ = 16A$.

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