3 and 4 .Determinants and Matrices
medium

यदि $P =\left[\begin{array}{lll}1 & \alpha & 3 \\ 1 & 3 & 3 \\ 2 & 4 & 4\end{array}\right] 3 \times 3$ आव्यूह $A$ का सहखण्डज है और $| A |=4$ तो $\alpha$ का मान है

A

$4$

B

$11$

C

$5$

D

$0$

(JEE MAIN-2013)

Solution

$|P|=1(12-12)-\alpha(4-6)+3(4-6)$

$=2 \alpha-6$

$|P|=|A|^{2}=16$

$2 \alpha-6=16$

$\alpha=11.$

Standard 12
Mathematics

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