MCQ
જો$A= \left[ \begin{matrix}\sin x & \cos x \\\cos x & -\sin x \\ \end{matrix} \right]$ અને$A\left( adj\,A \right)=kI,$તો$k=.........$
- A$1$
- ✓$-1$
- C$\sin x\cos x$
- D$-\sin x\cos x$
$A{\text{ }}\left( {adj{\text{ }}A} \right){\text{ }} = {\text{ }}\left| A \right|I$
$\therefore kI=|A|I$
$\therefore k=|A|=-\sin^2x-\cos^2x$
$=-1$
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