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Determinants — MATHS STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceMATHSDeterminants1 Mark
Question
Assertion (A) : The inverse of $A=\left(\begin{array}{ll}3 & 4 \\ 3 & 5\end{array}\right)$ does not exist.
Reason (R) : The matrix $A$ is non-singular.
✓

Answer

(a) : $\because|A|=\left|\begin{array}{ll}3 & 4 \\ 3 & 5\end{array}\right|=15-12=3 \neq 0$
$\therefore \quad A$ is non-singular.
$\therefore \quad A^{-1}$ exists.

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