Recent questions and answers in Linear Algebra

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1 1 answer
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For the matrix $A = \begin{bmatrix} 5 & 3 \\ 1 & 3 \end{bmatrix}$, ONE of the normalized eigen vectors is given as$\begin{pmatrix} \dfrac{1}{2} \\ \dfrac{\sqrt{3}}{2} \en...
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2 2 answers
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568 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
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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1 1 answer
538
538 views
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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1 1 answer
860
860 views
​​​​​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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317
317 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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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 $x^2+...
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431
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$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...
1 1 vote
0 0 answers
430
430 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$$\frac{1 + \sqrt{1561}}{12}$
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769
769 views
The system of linear equations in real $\left ( x,y \right )$ given by $$\left ( x \: y \right )\begin{bmatrix} 2 &5 - 2 \alpha \\ \alpha & 1 \end{bmatrix} = \left ( 0\:0...
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414
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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
797
797 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...
2 2 votes
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525
525 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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0 0 answers
472
472 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
868
868 views
A matrix $P$ is decomposed into its symmetric part $S$ and skew symmetric part $V$. If $$S= \begin{pmatrix} -4 & 4 & 2 \\ 4 & 3 & 7/2 \\ 2 & 7/2 & 2 \end{pmatrix}, \: \: ...
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434 views
Let $\textbf{I}$ be a $100$ dimensional identity matrix and $\textbf{E}$ be the set of its distinct (no value appears more than once in $\textbf{E})$ real eigen values. T...
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0 0 answers
332
332 views
Multiplication of real valued square matrices of same dimension isassociativecommutativealways positive definitenot always possible to compute
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1 1 answer
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962 views
Consider the matrix $A=\begin{bmatrix}50 &70 \\70 & 80\end{bmatrix}$ whose eigenvectors corresponding to eigenvalues $\lambda _{1}$ and $\lambda _{2}$ are $x_{1}=\begin{b...
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1 1 answer
738
738 views
In matrix equation $[A] \{X\}=\{R\}$,$[A] = \begin{bmatrix} 4 & 8 & 4 \\ 8 & 16 & -4 \\ 4 & -4 & 15 \end{bmatrix} \{X\} = \begin{Bmatrix} 2 \\ 1 \\ 4 \end{Bmatrix} \text{...
1 1 vote
1 1 answer
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Consider the matrix$$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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0 0 answers
478
478 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...
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420
420 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$
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459
459 views
$x+2y+z=4$$2x+y+2z=5$$x-y+z=1$The system of algebraic equations given above hasa unique solution of $x=1$, $y=1$ and $z=1$only the two solutions of $(x=1, y=1, z=1)$ and ...
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1 answers 1 answer
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425 views
If $A=\begin{bmatrix}1 & 2 & 3 \\ 0 & 4 & 5 \\ 0 & 0 & 1 \end{bmatrix}$ then $\text{det}(A^{-1})$ is _______ (correct to two decimal palces).
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262
262 views
The rank of the matrix $\begin{bmatrix} -4 & 1 & -1 \\ -1 & -1 & -1 \\ 7 & -3 & 1 \end{bmatrix}$ is$1$$2$$3$$4$
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1 1 answer
468
468 views
The determinant of a $2 \times 2$ matrix is $50$. If one eigenvalue of the matrix is $10$, the other eigenvalue is _________.
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1 answers 1 answer
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Which one of the following equations is a correct identity for arbitrary $3 \times 3$ real matrices $P$, $Q$ and $R$?$P(Q+R)=PQ+RP$$(P-Q)^2 = P^2 -2PQ -Q^2$$\text{det } ...
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464
464 views
Consider the matrix $P=\begin{bmatrix} \dfrac{1}{\sqrt{2}} & 0 &\dfrac{1}{\sqrt{2}} \\ 0 & 1 & 0\\ -\dfrac{1}{\sqrt{2}} &0 & \dfrac{1}{\sqrt{2}}\end{bmatrix}$ Which one ...
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0 0 answers
348
348 views
The product of eigenvalues of the matrix $P$ is$P=\begin{bmatrix}2 & 0 & 1\\ 4& -3 &3 \\ 0 & 2 & -1\end{bmatrix}$$-6$$2$$6$$-2$
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245 views
The number of linearly independent eigenvectors of matrix $A=\begin{bmatrix} 2 & 1 & 0\\ 0 &2 &0 \\ 0 & 0 & 3 \end{bmatrix}$ is _________
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315
315 views
A real square matrix $\textbf{A}$ is called skew-symmetric if$A^T=A$$A^T=A^{-1}$$A^T=-A$$A^T=A+A^{-1}$
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