If A = [ * 20 c 1&0&0 2&1&0 - 3 &2&1 ] , and B = [ * 20 c 1&0&0 -… - Vidyadip

MCQ

If $A = \left[ {\begin{array}{*{20}{c}}
1&0&0 \\
2&1&0 \\
{ - 3}&2&1
\end{array}} \right]\,$ and $B = \left[ {\begin{array}{*{20}{c}}
1&0&0 \\
{ - 2}&1&0 \\
7&{ - 2}&1
\end{array}} \right]$ then $AB$ equals

✓
$I$
B
$A$
C
$B$
D
$0$

✓

Answer

Correct option: A.

$I$

a
$A = \left[ {\begin{array}{*{20}{c}}
1&0&0\\
2&1&0\\
{ - 3}&2&1
\end{array}} \right],B = \left[ {\begin{array}{*{20}{c}}
1&0&0\\
{ - 2}&1&0\\
7&{ - 2}&1
\end{array}} \right]$

$AB = \left[ {\begin{array}{*{20}{c}}
1&0&0\\
0&1&0\\
0&0&1
\end{array}} \right] = I$

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 "M.C.Q (1 Marks)" from 3 and 4 . determinant and metrices→3 and 4 . determinant and metrices — all question types→Maths STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

$\int {\,\,\frac{{1 - {x^7}}}{{x(1 + {x^7})}}} $ $dx $ equals :

If $(\cos x)^y=(\cos y)^x$, then $\frac{d y}{d x}$ is equal to:

Let $S$ be the set of all $(\lambda, \mu)$ for which the vectors $\lambda \hat{ i }-\hat{ j }+\hat{ k }, \hat{ i }+2 \hat{ j }+\mu \hat{ k }$ and $3 \hat{ i }-4 \hat{ j }+5 \hat{ k }$, where $\lambda-\mu=5$, are coplanar, then $\sum_{(\lambda, \mu) \in S} 80\left(\lambda^2+\mu^2\right)$ is equal to :

If $A = {{{2^x}\cot x} \over {\sqrt x }},$ then ${{dA} \over {dx}} = $

Let $A\, \& \,B$ are two non singular matrices of order $3$ such that $A + B = I$ $\&$ $A^{-1} + B^{-1} = 2I,$ then $|adj(4AB)|,$ is (where $adj(A)$ is adjoint of matrix $A$) -

At $x=\frac{5 \pi}{6}, f(x)=2 \sin 3 x+3 \cos 3 x$ is

$\int {\frac{{\log x -log^2\ x+ x^2}}{{{x^3}}}} dx\,\,is\, $ (where $C$ is constant of integration)

If the ordinate $x = a$ divides the area bounded by the curve $y = \left( {1 + \frac{8}{{{x^2}}}} \right)\,,$ $x - $ axis and the ordinates $x = 2,$ $x = 4$ into two equal parts, then $a = $

The number of solutions of the system of equations:
2x + y − z = 7
x − 3y + 2z = 1
x + 4y − 3z = 5

3
2
1
0

Let $\vec{a}=\hat{i}+\hat{j}+\hat{k}, \vec{b}=\hat{i}-\hat{j}+\hat{k}$ and $\vec{c}=\hat{i}-\hat{j}-\hat{k}$ be three vectors. A vector $\vec{v}$ in the plane of $\vec{a}$ and $\vec{b}$, whose projection on $\vec{c}$ is $\frac{1}{\sqrt{3}}$, is given by