Difference between revisions of "031 Review Problems"
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| − | '''1.''' True or false: If all the entries of a <math>7\times 7</math> matrix <math>A</math> are <math>7,</math> then | + | '''1.''' True or false: If all the entries of a <math style="vertical-align: 0px">7\times 7</math> matrix <math style="vertical-align: 0px">A</math> are <math style="vertical-align: -4px">7,</math> then <math style="vertical-align: 0px">\text{det }A</math> must be <math style="vertical-align: 0px">7^7.</math> |
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| − | '''2.''' True or false: If a matrix <math>A^2</math> is diagonalizable, then the matrix <math>A</math> must be diagonalizable as well. | + | '''2.''' True or false: If a matrix <math style="vertical-align: 0px">A^2</math> is diagonalizable, then the matrix <math style="vertical-align: 0px">A</math> must be diagonalizable as well. |
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| − | '''3.''' True or false: If <math>A</math> is a <math>4\times 4</math> matrix with characteristic equation <math>\lambda(\lambda-1)(\lambda+1)(\lambda+e)=0,</math> then <math>A</math> is diagonalizable. | + | '''3.''' True or false: If <math style="vertical-align: 0px">A</math> is a <math style="vertical-align: -1px">4\times 4</math> matrix with characteristic equation <math style="vertical-align: -5px">\lambda(\lambda-1)(\lambda+1)(\lambda+e)=0,</math> then <math style="vertical-align: 0px">A</math> is diagonalizable. |
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| − | '''4.''' True or false: If <math>A</math> is invertible, then <math>A</math> is diagonalizable. | + | '''4.''' True or false: If <math style="vertical-align: 0px">A</math> is invertible, then <math style="vertical-align: 0px">A</math> is diagonalizable. |
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| − | '''5.''' True or false: If <math>A</math> and <math>B</math> are invertible <math>n\times n</math> matrices, then so is <math>A+B.</math> | + | '''5.''' True or false: If <math style="vertical-align: 0px">A</math> and <math style="vertical-align: 0px">B</math> are invertible <math style="vertical-align: 0px">n\times n</math> matrices, then so is <math style="vertical-align: -1px">A+B.</math> |
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| − | '''6.''' True or false: If <math>A</math> is a <math>3\times 5</math> matrix and | + | '''6.''' True or false: If <math style="vertical-align: 0px">A</math> is a <math style="vertical-align: 0px">3\times 5</math> matrix and <math style="vertical-align: -4px">\text{dim Nul }A=2,</math> then <math style="vertical-align: 0px">A\vec{x}=\vec{b}</math> is consistent for all <math style="vertical-align: 0px">\vec{b}</math> in <math style="vertical-align: 0px">\mathbb{R}^3.</math> |
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| − | '''7.''' True or false: Let <math>C=AB</math> for <math>4\times 4</math> matrices <math>A</math> and <math>B.</math> If <math>C</math> is invertible, then <math>A</math> is invertible. | + | '''7.''' True or false: Let <math style="vertical-align: 0px">C=AB</math> for <math style="vertical-align: 0px">4\times 4</math> matrices <math style="vertical-align: 0px">A</math> and <math style="vertical-align: 0px">B.</math> If <math style="vertical-align: 0px">C</math> is invertible, then <math style="vertical-align: 0px">A</math> is invertible. |
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| − | '''8.''' True or false: Let <math>W</math> be a subspace of <math>\mathbb{R}^4</math> and <math>\vec{v}</math> be a vector in <math>\mathbb{R}^4.</math> If <math>\vec{v}\in W</math> and <math>\vec{v}\in W^\perp,</math> then <math>\vec{v}=\vec{0}.</math> | + | '''8.''' True or false: Let <math style="vertical-align: 0px">W</math> be a subspace of <math style="vertical-align: 0px">\mathbb{R}^4</math> and <math style="vertical-align: 0px">\vec{v}</math> be a vector in <math style="vertical-align: 0px">\mathbb{R}^4.</math> If <math style="vertical-align: 0px">\vec{v}\in W</math> and <math style="vertical-align: -4px">\vec{v}\in W^\perp,</math> then <math style="vertical-align: 0px">\vec{v}=\vec{0}.</math> |
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| − | '''9.''' True or false: If <math>A</math> is an invertible <math>3\times 3</math> matrix, and <math>B</math> and <math>C</math> are <math>3\times 3</math> matrices such that <math>AB=AC,</math> then <math>B=C.</math> | + | '''9.''' True or false: If <math style="vertical-align: 0px">A</math> is an invertible <math style="vertical-align: 0px">3\times 3</math> matrix, and <math style="vertical-align: 0px">B</math> and <math style="vertical-align: 0px">C</math> are <math style="vertical-align: 0px">3\times 3</math> matrices such that <math style="vertical-align: -4px">AB=AC,</math> then <math style="vertical-align: 0px">B=C.</math> |
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'''10.''' | '''10.''' | ||
| − | (a) Is the matrix <math>A= | + | (a) Is the matrix <math style="vertical-align: -18px">A= |
\begin{bmatrix} | \begin{bmatrix} | ||
3 & 1 \\ | 3 & 1 \\ | ||
0 & 3 | 0 & 3 | ||
| − | \end{bmatrix}</math> diagonalizable? If so, explain why and diagonalize it. If not, explain why not. | + | \end{bmatrix}</math> diagonalizable? If so, explain why and diagonalize it. If not, explain why not. |
| − | (b) Is the matrix <math>A= | + | (b) Is the matrix <math style="vertical-align: -31px">A= |
\begin{bmatrix} | \begin{bmatrix} | ||
2 & 0 & -2 \\ | 2 & 0 & -2 \\ | ||
1 & 3 & 2 \\ | 1 & 3 & 2 \\ | ||
0 & 0 & 3 | 0 & 0 & 3 | ||
| − | \end{bmatrix}</math> diagonalizable? If so, explain why and diagonalize it. If not, explain why not. | + | \end{bmatrix}</math> diagonalizable? If so, explain why and diagonalize it. If not, explain why not. |
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|} | |} | ||
| − | '''11.''' Find the eigenvalues and eigenvectors of the matrix <math>A= | + | '''11.''' Find the eigenvalues and eigenvectors of the matrix <math style="vertical-align: -31px">A= |
\begin{bmatrix} | \begin{bmatrix} | ||
1 & 1 & 1 \\ | 1 & 1 & 1 \\ | ||
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|} | |} | ||
| − | '''12.''' Consider the matrix <math>A= | + | '''12.''' Consider the matrix <math style="vertical-align: -31px">A= |
\begin{bmatrix} | \begin{bmatrix} | ||
1 & -4 & 9 & -7 \\ | 1 & -4 & 9 & -7 \\ | ||
-1 & 2 & -4 & 1 \\ | -1 & 2 & -4 & 1 \\ | ||
5 & -6 & 10 & 7 | 5 & -6 & 10 & 7 | ||
| − | \end{bmatrix}</math> and assume that it is row equivalent to the matrix | + | \end{bmatrix}</math> and assume that it is row equivalent to the matrix |
| − | <math>B= | + | ::<math>B= |
\begin{bmatrix} | \begin{bmatrix} | ||
1 & 0 & -1 & 5 \\ | 1 & 0 & -1 & 5 \\ | ||
| Line 199: | Line 199: | ||
\end{bmatrix}.</math> | \end{bmatrix}.</math> | ||
| − | (a) List rank <math>A</math> and | + | (a) List rank <math style="vertical-align: 0px">A</math> and <math style="vertical-align: 0px">\text{dim Nul }A.</math> |
| − | (b) Find bases for | + | (b) Find bases for <math style="vertical-align: 0px">\text{Col }A</math> and <math style="vertical-align: 0px">\text{Nul }A.</math> Find an example of a nonzero vector that belongs to <math style="vertical-align: -5px">\text{Col }A,</math> as well as an example of a nonzero vector that belongs to <math style="vertical-align: 0px">\text{Nul }A.</math> |
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'''13.''' Find the dimension of the subspace spanned by the given vectors. Are these vectors linearly independent? | '''13.''' Find the dimension of the subspace spanned by the given vectors. Are these vectors linearly independent? | ||
| − | <math>\begin{bmatrix} | + | ::<math>\begin{bmatrix} |
1 \\ | 1 \\ | ||
0 \\ | 0 \\ | ||
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'''14.''' Let | '''14.''' Let | ||
| − | <math>B= | + | <math>B= |
\begin{bmatrix} | \begin{bmatrix} | ||
1 & -2 & 3 & 4\\ | 1 & -2 & 3 & 4\\ | ||
| Line 262: | Line 262: | ||
</math> | </math> | ||
| − | (a) Is <math>B</math> invertible? Explain. | + | (a) Is <math style="vertical-align: 0px">B</math> invertible? Explain. |
| − | (b) Define a linear transformation <math>T</math> by the formula <math>T(\vec{x})=B\vec{x}.</math> Is <math>T</math> onto? Explain. | + | (b) Define a linear transformation <math style="vertical-align: 0px">T</math> by the formula <math style="vertical-align: -5px">T(\vec{x})=B\vec{x}.</math> Is <math style="vertical-align: 0px">T</math> onto? Explain. |
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| − | '''15.''' Suppose <math>T</math> is a linear transformation given by the formula | + | '''15.''' Suppose <math style="vertical-align: 0px">T</math> is a linear transformation given by the formula |
| − | <math>T\Bigg( | + | ::<math>T\Bigg( |
\begin{bmatrix} | \begin{bmatrix} | ||
x_1 \\ | x_1 \\ | ||
| Line 293: | Line 293: | ||
\end{bmatrix}</math> | \end{bmatrix}</math> | ||
| − | (a) Find the standard matrix for <math>T.</math> | + | (a) Find the standard matrix for <math style="vertical-align: 0px">T.</math> |
| − | (b) Let <math>\vec{u}=7\vec{e_1}-4\vec{e_2}.</math> Find <math>T(\vec{u}).</math> | + | (b) Let <math style="vertical-align: -5px">\vec{u}=7\vec{e_1}-4\vec{e_2}.</math> Find <math style="vertical-align: -6px">T(\vec{u}).</math> |
| − | (c) Is <math>\begin{bmatrix} | + | (c) Is <math style="vertical-align: -21px">\begin{bmatrix} |
-1 \\ | -1 \\ | ||
3 | 3 | ||
| − | \end{bmatrix}</math> in the range of <math>T?</math> Explain. | + | \end{bmatrix}</math> in the range of <math style="vertical-align: 0px">T?</math> Explain. |
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|} | |} | ||
| − | '''16.''' Let <math>A</math> and <math>B</math> be <math>6\times 6</math> matrices with | + | '''16.''' Let <math style="vertical-align: 0px">A</math> and <math style="vertical-align: 0px">B</math> be <math style="vertical-align: 0px">6\times 6</math> matrices with <math style="vertical-align: -1px">\text{det }A=-10</math> and <math style="vertical-align: 0px">\text{det }B=5.</math> Use properties of determinants to compute: |
| − | + | (a) <math style="vertical-align: -2px">\text{det }3A</math> | |
| − | ( | + | (b) <math style="vertical-align: -7px">\text{det }(A^TB^{-1})</math> |
| − | |||
| − | |||
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| − | '''17.''' Let <math>A= | + | '''17.''' Let <math style="vertical-align: -20px">A= |
\begin{bmatrix} | \begin{bmatrix} | ||
5 & 1 \\ | 5 & 1 \\ | ||
| Line 342: | Line 340: | ||
\end{bmatrix}.</math> | \end{bmatrix}.</math> | ||
| − | (a) Find a basis for the eigenspace(s) of <math>A.</math> | + | (a) Find a basis for the eigenspace(s) of <math style="vertical-align: 0px">A.</math> |
| − | (b) Is the matrix <math>A</math> diagonalizable? Explain. | + | (b) Is the matrix <math style="vertical-align: 0px">A</math> diagonalizable? Explain. |
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|} | |} | ||
| − | '''18.''' Let <math>\vec{v}=\begin{bmatrix} | + | '''18.''' Let <math>\vec{v}=\begin{bmatrix} |
-1 \\ | -1 \\ | ||
3 \\ | 3 \\ | ||
0 | 0 | ||
| − | \end{bmatrix}</math> and <math>\vec{y}=\begin{bmatrix} | + | \end{bmatrix}</math> and <math>\vec{y}=\begin{bmatrix} |
2 \\ | 2 \\ | ||
0 \\ | 0 \\ | ||
| Line 369: | Line 367: | ||
\end{bmatrix}.</math> | \end{bmatrix}.</math> | ||
| − | (a) Find a unit vector in the direction of <math>\vec{v}.</math> | + | (a) Find a unit vector in the direction of <math style="vertical-align: 0px">\vec{v}.</math> |
| − | (b) Find the distance between <math>\vec{v}</math> and <math>\vec{y}.</math> | + | (b) Find the distance between <math style="vertical-align: 0px">\vec{v}</math> and <math style="vertical-align: -3px">\vec{y}.</math> |
| − | (c) Let <math>L= | + | (c) Let <math style="vertical-align: -5px">L=\text{Span }\{\vec{v}\}.</math> Compute the orthogonal projection of <math style="vertical-align: -3px">\vec{y}</math> onto <math style="vertical-align: 0px">L.</math> |
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|} | |} | ||
| − | '''19.''' Let <math>W= | + | '''19.''' Let <math>W=\text{Span }\Bigg\{\begin{bmatrix} |
2 \\ | 2 \\ | ||
0 \\ | 0 \\ | ||
| Line 398: | Line 396: | ||
0 \\ | 0 \\ | ||
0 | 0 | ||
| − | \end{bmatrix}\Bigg\}.</math> Is <math>\begin{bmatrix} | + | \end{bmatrix}\Bigg\}.</math> Is <math>\begin{bmatrix} |
2 \\ | 2 \\ | ||
6 \\ | 6 \\ | ||
4 \\ | 4 \\ | ||
0 | 0 | ||
| − | \end{bmatrix}</math> in <math>W^\perp?</math> Explain. | + | \end{bmatrix}</math> in <math style="vertical-align: 0px">W^\perp?</math> Explain. |
{| class="mw-collapsible mw-collapsed" style = "text-align:left;" | {| class="mw-collapsible mw-collapsed" style = "text-align:left;" | ||
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'''20.''' | '''20.''' | ||
| − | (a) Let <math>T:\mathbb{R}^2\rightarrow \mathbb{R}^2</math> be a transformation given by | + | (a) Let <math style="vertical-align: -2px">T:\mathbb{R}^2\rightarrow \mathbb{R}^2</math> be a transformation given by |
| − | <math>T\bigg( | + | ::<math>T\bigg( |
\begin{bmatrix} | \begin{bmatrix} | ||
x \\ | x \\ | ||
| Line 433: | Line 431: | ||
\end{bmatrix}.</math> | \end{bmatrix}.</math> | ||
| − | Determine whether <math>T</math> is a linear transformation. Explain. | + | Determine whether <math style="vertical-align: 0px">T</math> is a linear transformation. Explain. |
| − | (b) Let <math>A= | + | (b) Let <math style="vertical-align: -19px">A= |
\begin{bmatrix} | \begin{bmatrix} | ||
1 & -3 & 0 \\ | 1 & -3 & 0 \\ | ||
-4 & 1 &1 | -4 & 1 &1 | ||
| − | \end{bmatrix}</math> and <math>B= | + | \end{bmatrix}</math> and <math style="vertical-align: -32px">B= |
\begin{bmatrix} | \begin{bmatrix} | ||
2 & 1\\ | 2 & 1\\ | ||
1 & 0 \\ | 1 & 0 \\ | ||
-1 & 1 | -1 & 1 | ||
| − | \end{bmatrix}.</math> Find <math>AB, | + | \end{bmatrix}.</math> Find <math style="vertical-align: -4px">AB,~BA^T</math> and <math style="vertical-align: 0px">A-B^T.</math> |
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|} | |} | ||
| − | '''21.''' | + | '''21.''' Let <math style="vertical-align: -31px">A= |
| + | \begin{bmatrix} | ||
| + | 1 & 3 & 8 \\ | ||
| + | 2 & 4 &11\\ | ||
| + | 1 & 2 & 5 | ||
| + | \end{bmatrix}.</math> Find <math style="vertical-align: 0px">A^{-1}</math> if possible. | ||
| + | |||
{| class="mw-collapsible mw-collapsed" style = "text-align:left;" | {| class="mw-collapsible mw-collapsed" style = "text-align:left;" | ||
!Solution: | !Solution: | ||
| Line 473: | Line 477: | ||
|} | |} | ||
| − | '''22.''' | + | '''22.''' Find a formula for <math>\begin{bmatrix} |
| + | 1 & -6 \\ | ||
| + | 2 & -6 | ||
| + | \end{bmatrix}^k</math> by diagonalizing the matrix. | ||
| + | |||
{| class="mw-collapsible mw-collapsed" style = "text-align:left;" | {| class="mw-collapsible mw-collapsed" style = "text-align:left;" | ||
!Solution: | !Solution: | ||
| Line 488: | Line 496: | ||
'''23.''' | '''23.''' | ||
| + | |||
| + | (a) Show that if <math style="vertical-align: 0px">\vec{x}</math> is an eigenvector of the matrix <math style="vertical-align: 0px">A</math> corresponding to the eigenvalue 2, then <math style="vertical-align: 0px">\vec{x}</math> is an eigenvector of <math style="vertical-align: -2px">A^3-A^2+I.</math> What is the corresponding eigenvalue? | ||
| + | |||
| + | (b) Show that if <math style="vertical-align: -3px">\vec{y}</math> is an eigenvector of the matrix <math style="vertical-align: 0px">A</math> corresponding to the eigenvalue 3 and <math style="vertical-align: 0px">A</math> is invertible, then <math style="vertical-align: -3px">\vec{y}</math> is an eigenvector of <math style="vertical-align: 0px">A^{-1}.</math> What is the corresponding eigenvalue? | ||
| + | |||
{| class="mw-collapsible mw-collapsed" style = "text-align:left;" | {| class="mw-collapsible mw-collapsed" style = "text-align:left;" | ||
!Solution: | !Solution: | ||
| Line 501: | Line 514: | ||
|} | |} | ||
| − | '''24.''' | + | '''24.''' Let <math>A=\begin{bmatrix} |
| + | 3 & 0 & -1 \\ | ||
| + | 0 & 1 &-3\\ | ||
| + | 1 & 0 & 0 | ||
| + | \end{bmatrix}\begin{bmatrix} | ||
| + | 3 & 0 & 0 \\ | ||
| + | 0 & 4 &0\\ | ||
| + | 0 & 0 & 3 | ||
| + | \end{bmatrix}\begin{bmatrix} | ||
| + | 0 & 0 & 1 \\ | ||
| + | -3 & 1 &9\\ | ||
| + | -1 & 0 & 3 | ||
| + | \end{bmatrix}.</math> | ||
| + | |||
| + | Use the Diagonalization Theorem to find the eigenvalues of <math style="vertical-align: 0px">A</math> and a basis for each eigenspace. | ||
| + | |||
{| class="mw-collapsible mw-collapsed" style = "text-align:left;" | {| class="mw-collapsible mw-collapsed" style = "text-align:left;" | ||
!Solution: | !Solution: | ||
| Line 515: | Line 543: | ||
|} | |} | ||
| − | '''25.''' | + | '''25.''' Give an example of a <math style="vertical-align: 0px">3\times 3</math> matrix <math style="vertical-align: 0px">A</math> with eigenvalues 5,-1 and 3. |
| + | |||
{| class="mw-collapsible mw-collapsed" style = "text-align:left;" | {| class="mw-collapsible mw-collapsed" style = "text-align:left;" | ||
!Solution: | !Solution: | ||
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|} | |} | ||
| − | '''26.''' | + | '''26.''' Assume <math style="vertical-align: 0px">A^2=I.</math> Find <math style="vertical-align: -1px">\text{Nul }A.</math> |
| + | |||
{| class="mw-collapsible mw-collapsed" style = "text-align:left;" | {| class="mw-collapsible mw-collapsed" style = "text-align:left;" | ||
!Solution: | !Solution: | ||
| Line 543: | Line 573: | ||
|} | |} | ||
| − | '''27.''' | + | '''27.''' If <math style="vertical-align: 0px">A</math> is an <math style="vertical-align: 0px">n\times n</math> matrix such that <math style="vertical-align: -4px">AA^T=I,</math> what are the possible values of <math style="vertical-align: 0px">\text{det }A?</math> |
| + | |||
{| class="mw-collapsible mw-collapsed" style = "text-align:left;" | {| class="mw-collapsible mw-collapsed" style = "text-align:left;" | ||
!Solution: | !Solution: | ||
| Line 557: | Line 588: | ||
|} | |} | ||
| − | '''28.''' | + | '''28.''' Show that if <math style="vertical-align: 0px">\vec{x}</math> is an eigenvector of the matrix product <math style="vertical-align: 0px">AB</math> and <math style="vertical-align: -5px">B\vec{x}\ne \vec{0},</math> then <math style="vertical-align: 0px">B\vec{x}</math> is an eigenvector of <math style="vertical-align: 0px">BA.</math> |
| + | |||
{| class="mw-collapsible mw-collapsed" style = "text-align:left;" | {| class="mw-collapsible mw-collapsed" style = "text-align:left;" | ||
!Solution: | !Solution: | ||
| Line 572: | Line 604: | ||
'''29.''' | '''29.''' | ||
| + | |||
| + | (a) Suppose a <math style="vertical-align: 0px">6\times 8</math> matrix <math style="vertical-align: 0px">A</math> has 4 pivot columns. What is <math style="vertical-align: -1px">\text{dim Nul }A?</math> Is <math style="vertical-align: -1px">\text{Col }A=\mathbb{R}^4?</math> Why or why not? | ||
| + | |||
| + | (b) If <math style="vertical-align: 0px">A</math> is a <math style="vertical-align: 0px">7\times 5</math> matrix, what is the smallest possible dimension of <math style="vertical-align: -1px">\text{Nul }A?</math> | ||
| + | |||
{| class="mw-collapsible mw-collapsed" style = "text-align:left;" | {| class="mw-collapsible mw-collapsed" style = "text-align:left;" | ||
!Solution: | !Solution: | ||
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| − | '''30.''' | + | '''30.''' Consider the following system of equations. |
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| + | ::<math>x_1+kx_2=1</math> | ||
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| + | ::<math>3x_1+5x_2=2k</math> | ||
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| + | Find all real values of <math style="vertical-align: 0px">k</math> such that the system has only one solution. | ||
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{| class="mw-collapsible mw-collapsed" style = "text-align:left;" | {| class="mw-collapsible mw-collapsed" style = "text-align:left;" | ||
!Solution: | !Solution: | ||
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| − | '''31.''' | + | '''31.''' Suppose <math style="vertical-align: -5px">\{\vec{u},\vec{v}\}</math> is a basis of the eigenspace corresponding to the eigenvalue 0 of a <math style="vertical-align: 0px">5\times 5</math> matrix <math style="vertical-align: 0px">A.</math> |
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| + | (a) Is <math style="vertical-align: 0px">\vec{w}=\vec{u}-2\vec{v}</math> an eigenvector of <math style="vertical-align: 0px">A?</math> If so, find the corresponding eigenvalue. | ||
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| + | If not, explain why. | ||
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| + | (b) Find the dimension of <math style="vertical-align: -1px">\text{Col }A.</math> | ||
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{| class="mw-collapsible mw-collapsed" style = "text-align:left;" | {| class="mw-collapsible mw-collapsed" style = "text-align:left;" | ||
!Solution: | !Solution: | ||
Latest revision as of 13:11, 25 August 2017
This is a list of sample problems and is meant to represent the material usually covered in Math 31. An actual test may or may not be similar.
1. True or false: If all the entries of a Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle 7\times 7}
matrix are Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle 7,}
then Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\text{det }}A}
must be Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle 7^{7}.}
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2. True or false: If a matrix Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle A^{2}} is diagonalizable, then the matrix must be diagonalizable as well.
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3. True or false: If is a Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle 4\times 4} matrix with characteristic equation then is diagonalizable.
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4. True or false: If is invertible, then is diagonalizable.
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5. True or false: If and are invertible Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle n\times n} matrices, then so is Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle A+B.}
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6. True or false: If is a Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle 3\times 5} matrix and Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\text{dim Nul }}A=2,} then Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle A{\vec {x}}={\vec {b}}} is consistent for all Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\vec {b}}} in Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle \mathbb {R} ^{3}.}
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7. True or false: Let for Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle 4\times 4} matrices and Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle B.} If is invertible, then is invertible.
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8. True or false: Let Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle W} be a subspace of Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle \mathbb {R} ^{4}} and Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\vec {v}}} be a vector in Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle \mathbb {R} ^{4}.} If Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\vec {v}}\in W} and then Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\vec {v}}={\vec {0}}.}
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9. True or false: If is an invertible matrix, and and are matrices such that then Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle B=C.}
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10.
(a) Is the matrix Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle A={\begin{bmatrix}3&1\\0&3\end{bmatrix}}} diagonalizable? If so, explain why and diagonalize it. If not, explain why not.
(b) Is the matrix Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle A={\begin{bmatrix}2&0&-2\\1&3&2\\0&0&3\end{bmatrix}}} diagonalizable? If so, explain why and diagonalize it. If not, explain why not.
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11. Find the eigenvalues and eigenvectors of the matrix Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle A={\begin{bmatrix}1&1&1\\0&-1&1\\0&0&2\end{bmatrix}}.}
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12. Consider the matrix Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle A={\begin{bmatrix}1&-4&9&-7\\-1&2&-4&1\\5&-6&10&7\end{bmatrix}}} and assume that it is row equivalent to the matrix
(a) List rank and
(b) Find bases for and Find an example of a nonzero vector that belongs to as well as an example of a nonzero vector that belongs to
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13. Find the dimension of the subspace spanned by the given vectors. Are these vectors linearly independent?
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14. Let Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle B={\begin{bmatrix}1&-2&3&4\\0&3&0&0\\0&5&1&2\\0&-1&3&6\end{bmatrix}}.}
(a) Is invertible? Explain.
(b) Define a linear transformation by the formula Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle T({\vec {x}})=B{\vec {x}}.} Is onto? Explain.
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15. Suppose is a linear transformation given by the formula
- Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle T{\Bigg (}{\begin{bmatrix}x_{1}\\x_{2}\\x_{3}\\\end{bmatrix}}{\Bigg )}={\begin{bmatrix}5x_{1}-2.5x_{2}+10x_{3}\\-x_{1}+0.5x_{2}-2x_{3}\end{bmatrix}}}
(a) Find the standard matrix for Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle T.}
(b) Let Find
(c) Is in the range of Explain.
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16. Let and be Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle 6\times 6} matrices with Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\text{det }}A=-10} and Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\text{det }}B=5.} Use properties of determinants to compute:
(a) Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\text{det }}3A}
(b)
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17. Let Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle A={\begin{bmatrix}5&1\\0&5\end{bmatrix}}.}
(a) Find a basis for the eigenspace(s) of
(b) Is the matrix diagonalizable? Explain.
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18. Let Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\vec {v}}={\begin{bmatrix}-1\\3\\0\end{bmatrix}}} and Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\vec {y}}={\begin{bmatrix}2\\0\\5\end{bmatrix}}.}
(a) Find a unit vector in the direction of Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\vec {v}}.}
(b) Find the distance between Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\vec {v}}} and Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\vec {y}}.}
(c) Let Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle L={\text{Span }}\{{\vec {v}}\}.} Compute the orthogonal projection of Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\vec {y}}} onto
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19. Let Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle W={\text{Span }}{\Bigg \{}{\begin{bmatrix}2\\0\\-1\\0\end{bmatrix}},{\begin{bmatrix}-3\\1\\0\\0\end{bmatrix}}{\Bigg \}}.} Is Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle {\begin{bmatrix}2\\6\\4\\0\end{bmatrix}}} in Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle W^{\perp }?} Explain.
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20.
(a) Let Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle T:\mathbb {R} ^{2}\rightarrow \mathbb {R} ^{2}} be a transformation given by
- Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle T{\bigg (}{\begin{bmatrix}x\\y\end{bmatrix}}{\bigg )}={\begin{bmatrix}1-xy\\x+y\end{bmatrix}}.}
Determine whether is a linear transformation. Explain.
(b) Let Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle A={\begin{bmatrix}1&-3&0\\-4&1&1\end{bmatrix}}} and Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle B={\begin{bmatrix}2&1\\1&0\\-1&1\end{bmatrix}}.} Find Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle AB,~BA^T} and Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A-B^T.}
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21. Let Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A= \begin{bmatrix} 1 & 3 & 8 \\ 2 & 4 &11\\ 1 & 2 & 5 \end{bmatrix}.} Find Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A^{-1}} if possible.
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22. Find a formula for Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \begin{bmatrix} 1 & -6 \\ 2 & -6 \end{bmatrix}^k} by diagonalizing the matrix.
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23.
(a) Show that if Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \vec{x}} is an eigenvector of the matrix Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A} corresponding to the eigenvalue 2, then Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \vec{x}} is an eigenvector of Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A^3-A^2+I.} What is the corresponding eigenvalue?
(b) Show that if Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \vec{y}} is an eigenvector of the matrix Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A} corresponding to the eigenvalue 3 and Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A} is invertible, then Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \vec{y}} is an eigenvector of Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A^{-1}.} What is the corresponding eigenvalue?
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24. Let Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A=\begin{bmatrix} 3 & 0 & -1 \\ 0 & 1 &-3\\ 1 & 0 & 0 \end{bmatrix}\begin{bmatrix} 3 & 0 & 0 \\ 0 & 4 &0\\ 0 & 0 & 3 \end{bmatrix}\begin{bmatrix} 0 & 0 & 1 \\ -3 & 1 &9\\ -1 & 0 & 3 \end{bmatrix}.}
Use the Diagonalization Theorem to find the eigenvalues of Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A} and a basis for each eigenspace.
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25. Give an example of a Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 3\times 3} matrix Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A} with eigenvalues 5,-1 and 3.
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26. Assume Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A^2=I.} Find Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \text{Nul }A.}
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27. If Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A} is an Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle n\times n} matrix such that Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle AA^T=I,} what are the possible values of Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \text{det }A?}
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28. Show that if Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \vec{x}} is an eigenvector of the matrix product Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle AB} and Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle B\vec{x}\ne \vec{0},} then Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle B\vec{x}} is an eigenvector of Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle BA.}
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29.
(a) Suppose a Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 6\times 8} matrix Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A} has 4 pivot columns. What is Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \text{dim Nul }A?} Is Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \text{Col }A=\mathbb{R}^4?} Why or why not?
(b) If Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A} is a Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 7\times 5} matrix, what is the smallest possible dimension of Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \text{Nul }A?}
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30. Consider the following system of equations.
- Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle x_1+kx_2=1}
- Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 3x_1+5x_2=2k}
Find all real values of Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle k} such that the system has only one solution.
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31. Suppose Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \{\vec{u},\vec{v}\}} is a basis of the eigenspace corresponding to the eigenvalue 0 of a Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 5\times 5} matrix Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A.}
(a) Is Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \vec{w}=\vec{u}-2\vec{v}} an eigenvector of Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A?} If so, find the corresponding eigenvalue.
If not, explain why.
(b) Find the dimension of Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \text{Col }A.}
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