If A= [ ll 3 & 2 1 & 4 ], then A(adj A)= - Vidyadip

MCQ

If $A=\left[\begin{array}{ll}3 & 2 \\ 1 & 4\end{array}\right]$, then $A(\operatorname{adj} A)=$

✓
$\left[\begin{array}{cc}10 & 0 \\ 0 & 10\end{array}\right]$
B
$\left[\begin{array}{cc}0 & 10 \\ 10 & 0\end{array}\right]$
C
$\left[\begin{array}{cc}10 & 1 \\ 1 & 10\end{array}\right]$
D
None of these

✓

Answer

Correct option: A.

$\left[\begin{array}{cc}10 & 0 \\ 0 & 10\end{array}\right]$

(A) Using Shortcut 4(i),
$A (\operatorname{adj} A )=| A | \cdot I _{ n }$
$\therefore \quad A (\operatorname{adj} A )=\left|\begin{array}{ll}3 & 2 \\ 1 & 4\end{array}\right|\left[\begin{array}{ll}1 & 0 \\ 0 & 1\end{array}\right]=\left[\begin{array}{cc}10 & 0 \\ 0 & 10\end{array}\right]$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "MCQ" from Matrics→Matrics — all question types→Maths STD 12 Science question papers→Maharashtra Board STD 12 Science question papers→Maharashtra Board question paper generator→

Similar questions

If $\bar{a}=\frac{1}{\sqrt{10}}(3 \hat{i}+\hat{k}), \bar{b}=\frac{1}{7}(2 \hat{i}+3 \hat{j}-6 \hat{k})$, then the value of $(2 \bar{a}-\bar{b}) \cdot\{(\bar{a} \times \bar{b}) \times(\bar{a}+2 \bar{b})\}$ is

The area bounded by the curve $\text{y}=\sin\text{x}$ between the ordinates $\text{x}=0,\text{x}=\pi$ and the $x-$axis is:

A fair die with numbers 1 to 6 on their faces is thrown. Let $X$ denote the number of factors of the number, on the uppermost face, then the probability distribution of $X$ is

The value of $\int_{-1}^1 \frac{\sin x-x^2}{3-|x|} d x$ is

if $x$ lies in the interval $[0, 1]$, then the least value of $x^2 + x + 1$ is :

$\int_{-3}^3 \cot ^{-1} x d x=$

If for the matrix $A, A^3 = I$, than $A^{-1} =$

Let $\overline{ A }=(x+4 y) \overline{ a }+(2 x+y+1) \overline{ b }$ and $\overline{ B }=(y-2 x+2) \overline{ a }+(2 x-3 y-1) \overline{ b }$, where $\bar{a}$ and $\bar{b}$ are non-collinear vectors, if $3 \overline{A}=2 \overline{B} ;$ then

Which of the following statements is correct?

If g(1) = g(2), then $\int_1^2[ f \{ g (x)\}]^{-1} f ^{\prime}[ g (x)] g ^{\prime}(x) d x$ is equal to