CBSE Class 12 Sample Paper for 2021 Boards

Class 12
Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

## If A is a square matrix of order 3 such that π΄ 2 = 2π΄, then find the value of |A|.

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Question 20 (Choice 1) If A is a square matrix of order 3 such that π΄2 = 2π΄, then find the value of |A|. Given A2 = 2A Taking Determinant both sides |π¨^π | = |2π΄| |π¨ Γ π¨| = |2π΄| |π΄||π΄| = |ππ¨| Since order of matrix is 3, using|ππ΄|=π^π |π΄| |π΄||π΄| = π^π |π¨| |π΄||π΄| = 8|π΄| |π΄||π΄| β 8|π΄| = 0 |π΄| (|π΄|β"8" ) = 0 Thus, |π¨| = 0 or |π¨| = 8

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