Recent questions in Linear Algebra

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1 1 answer
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Let $\mathbf{A}$ and $\mathbf{B}$ be real symmetric matrices of same size. Which one of the following options is correct?$\mathbf{A}^{\mathrm{T}}=\mathrm{A}^{-1}$$\mathbf...
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300
300 views
Consider the second-order linear ordinary differential equationx ^ 2 * (d ^ 2 * y)/(d * x ^ 2) + x * d/dx (y) - y = 0with the initial conditionsy(x = 1) = 6 ,The value of...
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​​​​​Consider the system of linear equations\[\begin{array}{c}x+2 y+z=5 \\2 x+a y+4 z=12 \\2 x+4 y+6 z=b\end{array}\]The values of $a$ and $b$ such that there exists a no...
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1 1 answer
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​​​​The matrix $\left[\begin{array}{ll}1 & a \\ 8 & 3\end{array}\right]$ (where $a>0$ ) has a negative eigenvalue if $a$ is greater than$\frac{3}{8}$$\frac{1}{8}$$\frac{1...
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A linear transformation maps a point $(x, y)$ in the plane to the point $(\hat{x}, \hat{y})$ according to the rule$$\hat{x}=3 y, \quad \hat{y}=2 x .$$Then, the disc $x^2+...
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416
416 views
$A$ is a $3 \times 5$ real matrix of rank $2$. For the set ot homogeneous equations $Ax = 0$, where $0$ is a zero vector and $x$ is a vector of unknown variables, which o...
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2 2 answers
521
521 views
If the sum and product of eigenvalues of a $2 \times 2$ real matrix $\begin{bmatrix} 3 & p\\ p & q \end{bmatrix}$ are $4$ and $-1$ respectively, then $\left | p \right |$...
1 1 vote
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411
411 views
If $A = \begin{bmatrix} 10 & 2k +5 \\ 3k - 3 & k +5 \end{bmatrix}$ is a symmetric matrix, the value of $k$ is __________________.$8$$5$$-0.4$$\frac{1 + \sqrt{1561}}{12}$
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750
750 views
The system of linear equations in real $\left ( x,y \right )$ given by $$\left ( x \: y \right )\begin{bmatrix} 2 &5 - 2 \alpha \\ \alpha & 1 \end{bmatrix} = \left ( 0\:0...
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394
394 views
Consider two vectors: $$\vec{a} = 5 i + 7j + 2k$$$$\vec{b} = 3 i - j + 6k$$Magnitude of the component of $\vec{a}$ orthogonal to $\vec{b}$ in the plane containing the vec...
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1 1 answer
768
768 views
Consider an $n \times n$ matrix $\text{A}$ and a non-zero $n \times 1$ vector $p.$ Their product $Ap=\alpha ^{2}p$, where $\alpha \in \Re$ and $\alpha \notin \left \{ -1...
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501
501 views
Let the superscript $\text{T}$ represent the transpose operation. Consider the function $f(x)=\frac{1}{2}x^TQx-r^Tx$, where $x$ and $r$ are $n \times 1$ vectors and $\tex...
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443
443 views
Consider a vector $\text{p}$ in $2$-dimensional space. Let its direction (counter-clockwise angle with the positive $\text{x}$-axis) be $\theta$. Let $\text{p}$ be an ei...
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1 1 answer
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836 views
A matrix $P$ is decomposed into its symmetric part $S$ and skew symmetric part $V$. If $$S= \begin{pmatrix} -4 & 4 & 2 \\ 4 & 3 & 7/2 \\ 2 & 7/2 & 2 \end{pmatrix}, \: \: ...
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418
418 views
Let $\textbf{I}$ be a $100$ dimensional identity matrix and $\textbf{E}$ be the set of its distinct (no value appears more than once in $\textbf{E})$ real eigen values. T...
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0 0 answers
312
312 views
Multiplication of real valued square matrices of same dimension isassociativecommutativealways positive definitenot always possible to compute
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1 1 answer
699
699 views
In matrix equation $[A] \{X\}=\{R\}$,$[A] = \begin{bmatrix} 4 & 8 & 4 \\ 8 & 16 & -4 \\ 4 & -4 & 15 \end{bmatrix} \{X\} = \begin{Bmatrix} 2 \\ 1 \\ 4 \end{Bmatrix} \text{...
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465
465 views
The transformation matrix for mirroring a point in $x – y$ plane about the line $y=x$ is given by$\begin{bmatrix} 1 & 0 \\ 0 & -1 \end{bmatrix} \\$$\begin{bmatrix} -1 & 0...
1 1 vote
1 1 answer
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Consider the matrix$$P=\begin{bmatrix} 1 & 1 & 0 \\ 0 & 1 & 1 \\ 0 & 0 & 1 \end{bmatrix}$$The number of distinct eigenvalues$0$$1$$2$$3$
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403
403 views
The set of equations $$\begin{array}{l} x+y+z=1 \\ ax-ay+3z=5 \\ 5x-3y+az=6 \end{array}$$has infinite solutions, if $a=$$-3$$3$$4$$-4$