3 and 4 .Determinants and Matrices
medium

જો $P = \left[ {\begin{array}{*{20}{c}}1&\alpha &3\\1&3&3\\2&4&4\end{array}} \right]$ એ $3×3 $ શ્રેણિક $A$  નો સહઅવયવજ હોય અને $ |A|=4$  તો $\alpha $ મેળવો.

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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