- Home
- Standard 12
- Mathematics
3 and 4 .Determinants and Matrices
easy
જો $A = \left[ {\begin{array}{*{20}{c}}i&0\\0&i\end{array}} \right]$, તો ${A^2} = $
A
$\left[ {\begin{array}{*{20}{c}}1&0\\0&{ - 1}\end{array}} \right]$
B
$\left[ {\begin{array}{*{20}{c}}{ - 1}&0\\0&{ - 1}\end{array}} \right]$
C
$\left[ {\begin{array}{*{20}{c}}1&0\\0&1\end{array}} \right]$
D
$\left[ {\begin{array}{*{20}{c}}{ - 1}&0\\0&1\end{array}} \right]$
Solution
(b) $A = \left[ {\begin{array}{*{20}{c}}i&0\\0&i\end{array}} \right]$; ${A^2} = A.\,A = \left[ {\begin{array}{*{20}{c}}i&0\\0&i\end{array}} \right]\,\left[ {\begin{array}{*{20}{c}}i&0\\0&i\end{array}} \right]$
${A^2} = \left[ {\begin{array}{*{20}{c}}{ – 1}&0\\0&{ – 1}\end{array}} \right]$,
$[\because {i^2} = – 1]$ .
Standard 12
Mathematics