Question bank/JEE Main/Mathematics

JEE MainMathematicsToughMatrix and determinants

Let is a square matrix of order 2 where a_ij∈\in
then number of matrices A such that A^-1 exists is

λ\lambda then λ\lambda- 300 is (given that all elements of matrix A
are distinct)

Show answer and solution
For A^-1 exists ∣A∣≠0|A| \neq 0
Case - I: Exactly one element is zero

Case - ll: No element is zero

$A = \left| \begin{matrix}

a\ \ \ \ b \\

c\ \ \ \ d

\end{matrix} \right|$

∣A∣|A|= ad - bc = 0 ad = bc = 6 8\boxed{8}
ad = bc = 12
8\boxed{8}
⇒×⌊4−16=120−16\Rightarrow \times \lfloor 4 - 16 = 120 - 16
= 104

Total = 344

Source: Grass-G / M-23 Mathematics Paper 31 Dec FST.docx

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