Question
If $\text{A}=\begin{bmatrix} 3\\5\\2\end{bmatrix}$ and $\text{B}=\begin{bmatrix}1&0&4\end{bmatrix},$ verify that $(AB)^T = B^TA^T.$

Answer

Given,
$\text{A}=\begin{bmatrix}3\\5\\2 \end{bmatrix},\text{B}=\begin{bmatrix}1&0&4\end{bmatrix}$
$\text{AB}^\text{T}=\text{B}^\text{T}\text{A}^\text{T }$
$\Rightarrow\begin{pmatrix}\begin{bmatrix}3\\5\\2\end{bmatrix}\begin{bmatrix}1&0&4 \end{bmatrix}\end{pmatrix}^\text{T}=\begin{bmatrix}1&0&4\end{bmatrix}^\text{T}\begin{bmatrix}3\\5\\2\end{bmatrix}^\text{T}$
$\Rightarrow\begin{bmatrix}3&0&12\\5&0&20\\2&0&8\end{bmatrix}^\text{T}=\begin{bmatrix}1\\0\\4\end{bmatrix}\begin{bmatrix}3&5&2 \end{bmatrix}$
$\Rightarrow\begin{bmatrix} 3&5&2\\0&0&0\\12&20&8\end{bmatrix}=\begin{bmatrix} 3&5&2\\0&0&0\\12&20&8\end{bmatrix}$
$\Rightarrow\text{LHS}=\text{RHS}$
So,
$(\text{AB})^\text{T}=\text{B}^\text{T}\text{A}^\text{T}$

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

Similar questions

Evaluate the following :

$\tan ^{-1}(1)+\cos ^{-1}\left(\frac{1}{2}\right)+\sin ^{-1}\left(\frac{1}{2}\right)$

$\int(\text{x}+2)\sqrt{3\text{x}+5}\text{ dx}$
Prove the following :

$\tan ^{-1}\left[\frac{\cos \theta+\sin \theta}{\cos \theta-\sin \theta}\right]=\frac{\pi}{4}+\theta$ if $\theta \in\left(-\frac{\pi}{4}, \frac{\pi}{4}\right)$

A farmer mixes two brands P and Q of cattle feed. Brand P, costing Rs. 250 per bag, contains 3 units of nutritional element A, 2.5 units of element B and 2 units of element C. Brand Q costing Rs. 200 per bag contains 1.5 units of nutritional element A, 11.25 units of element B and 3 units of element C. The minimum requirements of nutrients A, B and C are 18 units, 45 units and 24 units respectively. Determine the number of bags of each brand which should be mixed in order to produce a mixture having a minimum cost per bag? What is the minimum cost of the mixture per bag?
For the following matrices verify the distributivity of matrix, multiplication over matrix addtion i.e., A(B + C) = AB + AC.
$\text{A}=\begin{bmatrix}2&-1\\1&1\\-1&2\end{bmatrix},\text{B}=\begin{bmatrix}0&1\\1&1\end{bmatrix}$ and $\text{C}=\begin{bmatrix}1&-1\\0&1\end{bmatrix}$
Differentiate the following w.r.t. x:

$x^{x^x}+e^{x^x}$

Evaluate the following intregals:
$\int\frac{\sin2\text{x}}{(1+\sin\text{x})(2+\sin\text{x})}\text{ dx}$
Suppose $f_1$ and $f_2$​​​​​​​ are non-zero one-one functions from R to R. Is $\frac{\text{f}_1}{\text{f}_2}$ necessarily one-one? Justify your answer. Here, $\frac{\text{f}_1}{\text{f}_2}:\text{R}\rightarrow\ \text{R}$ is given by $\Big(\frac{\text{f}_1}{\text{f}_2}\Big)(\text{x})=\frac{\text{f}_1(\text{x})}{\text{f}_2(\text{x})}$ for all $\text{x}\in\text{R}.$
If f(x) is a continuous function defind on [-a, a], then prove that:$\int\limits^{\text{a}}_{-\text{a}}\text{f(x)}\text{dx}=\int\limits^{\text{a}}_0\big\{\text{f(x)}+\text{f}(-\text{x})\big\}\text{dx}$
In the following, determine the values of constants involved in the definition so that the given function is continuous:
$\text{f(x)}=\begin{cases}2,&\text{if }\text{ x}\leq3\\\text{ax}+\text{b},&\text{if }3<\text{ x}<5\\9,&\text{if }\text{ x}\geq5\end{cases}$