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કિમત મેળવો : $\left[\begin{array}{cc}a & b \\ -b & a\end{array}\right]\left[\begin{array}{lc}a & -b \\ b & a\end{array}\right]$
$\left[\begin{array}{cc}a^{2}+b^{2} & 0 \\ 0 & a^{2}+b^{2}\end{array}\right]$
$\left[\begin{array}{cc}a^{2}+b^{2} & 0 \\ 0 & a^{2}+b^{2}\end{array}\right]$
$\left[\begin{array}{cc}a^{2}+b^{2} & 0 \\ 0 & a^{2}+b^{2}\end{array}\right]$
$\left[\begin{array}{cc}a^{2}+b^{2} & 0 \\ 0 & a^{2}+b^{2}\end{array}\right]$
Solution
$\left[\begin{array}{cc}a & b \\ -b & a\end{array}\right]\left[\begin{array}{lc}a & -b \\ b & a\end{array}\right]$
$=\left[\begin{array}{cc}a(a)+b(b) & a(-b)+b(a) \\ -b(a)+a(b) & -b(-b)+a(a)\end{array}\right]$
$ = \left[ {\begin{array}{*{20}{c}}
{{a^2} + {b^2}}&{ – ab + ab} \\
{ – ab + ab}&{{b^2} + {a^2}}
\end{array}} \right]$ $ = \left[ {\begin{array}{*{20}{c}}
{{a^2} + {b^2}}&0 \\
0&{{a^2} + {b^2}}
\end{array}} \right]$
