Matrix vector form. Is this in the correct form?

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I have this question:




Write the linear system
$$beginarrayrcr-2x_1+x_2-4x_3 & = & 1 \ x_1-2x_2 & = & -3 \ x_1+x_2-4x_3 & = & 0 endarray$$
in the matrix-vector form $Amathbfx=mathbfb$.




Is this what they want?



$$
x_1*
beginbmatrix
-2 \ 1 \ 1
endbmatrix
+
x_2*
beginbmatrix
1 \ -2 \ 1
endbmatrix
+
x_3*
beginbmatrix
-4 \ 0 \ -4
endbmatrix
=
beginbmatrix
1 \ -3 \ 0
endbmatrix
$$







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  • For general MathJax tips, you can take a look here : math.meta.stackexchange.com/questions/5020/… (See in particular the top-voted answer for matrices).
    – Arnaud D.
    Aug 1 at 18:48














up vote
3
down vote

favorite












I have this question:




Write the linear system
$$beginarrayrcr-2x_1+x_2-4x_3 & = & 1 \ x_1-2x_2 & = & -3 \ x_1+x_2-4x_3 & = & 0 endarray$$
in the matrix-vector form $Amathbfx=mathbfb$.




Is this what they want?



$$
x_1*
beginbmatrix
-2 \ 1 \ 1
endbmatrix
+
x_2*
beginbmatrix
1 \ -2 \ 1
endbmatrix
+
x_3*
beginbmatrix
-4 \ 0 \ -4
endbmatrix
=
beginbmatrix
1 \ -3 \ 0
endbmatrix
$$







share|cite|improve this question





















  • For general MathJax tips, you can take a look here : math.meta.stackexchange.com/questions/5020/… (See in particular the top-voted answer for matrices).
    – Arnaud D.
    Aug 1 at 18:48












up vote
3
down vote

favorite









up vote
3
down vote

favorite











I have this question:




Write the linear system
$$beginarrayrcr-2x_1+x_2-4x_3 & = & 1 \ x_1-2x_2 & = & -3 \ x_1+x_2-4x_3 & = & 0 endarray$$
in the matrix-vector form $Amathbfx=mathbfb$.




Is this what they want?



$$
x_1*
beginbmatrix
-2 \ 1 \ 1
endbmatrix
+
x_2*
beginbmatrix
1 \ -2 \ 1
endbmatrix
+
x_3*
beginbmatrix
-4 \ 0 \ -4
endbmatrix
=
beginbmatrix
1 \ -3 \ 0
endbmatrix
$$







share|cite|improve this question













I have this question:




Write the linear system
$$beginarrayrcr-2x_1+x_2-4x_3 & = & 1 \ x_1-2x_2 & = & -3 \ x_1+x_2-4x_3 & = & 0 endarray$$
in the matrix-vector form $Amathbfx=mathbfb$.




Is this what they want?



$$
x_1*
beginbmatrix
-2 \ 1 \ 1
endbmatrix
+
x_2*
beginbmatrix
1 \ -2 \ 1
endbmatrix
+
x_3*
beginbmatrix
-4 \ 0 \ -4
endbmatrix
=
beginbmatrix
1 \ -3 \ 0
endbmatrix
$$









share|cite|improve this question












share|cite|improve this question




share|cite|improve this question








edited Aug 1 at 18:42









Arnaud D.

14.5k52141




14.5k52141









asked Aug 1 at 18:20









Jwan622

1,60111224




1,60111224











  • For general MathJax tips, you can take a look here : math.meta.stackexchange.com/questions/5020/… (See in particular the top-voted answer for matrices).
    – Arnaud D.
    Aug 1 at 18:48
















  • For general MathJax tips, you can take a look here : math.meta.stackexchange.com/questions/5020/… (See in particular the top-voted answer for matrices).
    – Arnaud D.
    Aug 1 at 18:48















For general MathJax tips, you can take a look here : math.meta.stackexchange.com/questions/5020/… (See in particular the top-voted answer for matrices).
– Arnaud D.
Aug 1 at 18:48




For general MathJax tips, you can take a look here : math.meta.stackexchange.com/questions/5020/… (See in particular the top-voted answer for matrices).
– Arnaud D.
Aug 1 at 18:48










2 Answers
2






active

oldest

votes

















up vote
6
down vote













I guess the matrix-vector form here refers to the matrix A and the vector b. I would suggest to rewrite the equation in the following way



$$beginpmatrix-2&1&-4\1&-2&0\1&1&-4endpmatrixbeginpmatrixx_1\x_2\x_3endpmatrix~=~beginpmatrix1\-3\0endpmatrix$$



To verify the L.H.S. you can just multiply the vector by the matrix and then your will get first guess.






share|cite|improve this answer























  • What does pmatrix mean?
    – Jwan622
    Aug 1 at 18:45










  • Why is the column of x's called a vector?
    – Jwan622
    Aug 1 at 18:46










  • The pmatrix-command gives you the $()$ braces. For other kinds of matrices just search for the LaTeX commands. How would you call a single column instead?
    – mrtaurho
    Aug 1 at 18:47











  • You can interpret this system of equation as the point of intersection within $mathbbR^3$ of the three given functions. For that every single variable represents on direction of the $3$-dimensional space you can just conclude setting the vector x as $beginpmatrixx_1\x_2\x_3endpmatrix$ where $x_1,x_2,x_3$ are the three directions towards the the $mathbbR^3$-space.
    – mrtaurho
    Aug 1 at 18:54


















up vote
1
down vote













basically!



$
A = beginpmatrix -2 & 1 & -4 \ 1 & -2 & 0 \ 1 & 1 & -4 endpmatrix
$
and $b = beginpmatrix 1 \ -3 \ 0 endpmatrix$ yielding $Ax = b$.






share|cite|improve this answer





















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    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    6
    down vote













    I guess the matrix-vector form here refers to the matrix A and the vector b. I would suggest to rewrite the equation in the following way



    $$beginpmatrix-2&1&-4\1&-2&0\1&1&-4endpmatrixbeginpmatrixx_1\x_2\x_3endpmatrix~=~beginpmatrix1\-3\0endpmatrix$$



    To verify the L.H.S. you can just multiply the vector by the matrix and then your will get first guess.






    share|cite|improve this answer























    • What does pmatrix mean?
      – Jwan622
      Aug 1 at 18:45










    • Why is the column of x's called a vector?
      – Jwan622
      Aug 1 at 18:46










    • The pmatrix-command gives you the $()$ braces. For other kinds of matrices just search for the LaTeX commands. How would you call a single column instead?
      – mrtaurho
      Aug 1 at 18:47











    • You can interpret this system of equation as the point of intersection within $mathbbR^3$ of the three given functions. For that every single variable represents on direction of the $3$-dimensional space you can just conclude setting the vector x as $beginpmatrixx_1\x_2\x_3endpmatrix$ where $x_1,x_2,x_3$ are the three directions towards the the $mathbbR^3$-space.
      – mrtaurho
      Aug 1 at 18:54















    up vote
    6
    down vote













    I guess the matrix-vector form here refers to the matrix A and the vector b. I would suggest to rewrite the equation in the following way



    $$beginpmatrix-2&1&-4\1&-2&0\1&1&-4endpmatrixbeginpmatrixx_1\x_2\x_3endpmatrix~=~beginpmatrix1\-3\0endpmatrix$$



    To verify the L.H.S. you can just multiply the vector by the matrix and then your will get first guess.






    share|cite|improve this answer























    • What does pmatrix mean?
      – Jwan622
      Aug 1 at 18:45










    • Why is the column of x's called a vector?
      – Jwan622
      Aug 1 at 18:46










    • The pmatrix-command gives you the $()$ braces. For other kinds of matrices just search for the LaTeX commands. How would you call a single column instead?
      – mrtaurho
      Aug 1 at 18:47











    • You can interpret this system of equation as the point of intersection within $mathbbR^3$ of the three given functions. For that every single variable represents on direction of the $3$-dimensional space you can just conclude setting the vector x as $beginpmatrixx_1\x_2\x_3endpmatrix$ where $x_1,x_2,x_3$ are the three directions towards the the $mathbbR^3$-space.
      – mrtaurho
      Aug 1 at 18:54













    up vote
    6
    down vote










    up vote
    6
    down vote









    I guess the matrix-vector form here refers to the matrix A and the vector b. I would suggest to rewrite the equation in the following way



    $$beginpmatrix-2&1&-4\1&-2&0\1&1&-4endpmatrixbeginpmatrixx_1\x_2\x_3endpmatrix~=~beginpmatrix1\-3\0endpmatrix$$



    To verify the L.H.S. you can just multiply the vector by the matrix and then your will get first guess.






    share|cite|improve this answer















    I guess the matrix-vector form here refers to the matrix A and the vector b. I would suggest to rewrite the equation in the following way



    $$beginpmatrix-2&1&-4\1&-2&0\1&1&-4endpmatrixbeginpmatrixx_1\x_2\x_3endpmatrix~=~beginpmatrix1\-3\0endpmatrix$$



    To verify the L.H.S. you can just multiply the vector by the matrix and then your will get first guess.







    share|cite|improve this answer















    share|cite|improve this answer



    share|cite|improve this answer








    edited Aug 1 at 21:47


























    answered Aug 1 at 18:24









    mrtaurho

    650117




    650117











    • What does pmatrix mean?
      – Jwan622
      Aug 1 at 18:45










    • Why is the column of x's called a vector?
      – Jwan622
      Aug 1 at 18:46










    • The pmatrix-command gives you the $()$ braces. For other kinds of matrices just search for the LaTeX commands. How would you call a single column instead?
      – mrtaurho
      Aug 1 at 18:47











    • You can interpret this system of equation as the point of intersection within $mathbbR^3$ of the three given functions. For that every single variable represents on direction of the $3$-dimensional space you can just conclude setting the vector x as $beginpmatrixx_1\x_2\x_3endpmatrix$ where $x_1,x_2,x_3$ are the three directions towards the the $mathbbR^3$-space.
      – mrtaurho
      Aug 1 at 18:54

















    • What does pmatrix mean?
      – Jwan622
      Aug 1 at 18:45










    • Why is the column of x's called a vector?
      – Jwan622
      Aug 1 at 18:46










    • The pmatrix-command gives you the $()$ braces. For other kinds of matrices just search for the LaTeX commands. How would you call a single column instead?
      – mrtaurho
      Aug 1 at 18:47











    • You can interpret this system of equation as the point of intersection within $mathbbR^3$ of the three given functions. For that every single variable represents on direction of the $3$-dimensional space you can just conclude setting the vector x as $beginpmatrixx_1\x_2\x_3endpmatrix$ where $x_1,x_2,x_3$ are the three directions towards the the $mathbbR^3$-space.
      – mrtaurho
      Aug 1 at 18:54
















    What does pmatrix mean?
    – Jwan622
    Aug 1 at 18:45




    What does pmatrix mean?
    – Jwan622
    Aug 1 at 18:45












    Why is the column of x's called a vector?
    – Jwan622
    Aug 1 at 18:46




    Why is the column of x's called a vector?
    – Jwan622
    Aug 1 at 18:46












    The pmatrix-command gives you the $()$ braces. For other kinds of matrices just search for the LaTeX commands. How would you call a single column instead?
    – mrtaurho
    Aug 1 at 18:47





    The pmatrix-command gives you the $()$ braces. For other kinds of matrices just search for the LaTeX commands. How would you call a single column instead?
    – mrtaurho
    Aug 1 at 18:47













    You can interpret this system of equation as the point of intersection within $mathbbR^3$ of the three given functions. For that every single variable represents on direction of the $3$-dimensional space you can just conclude setting the vector x as $beginpmatrixx_1\x_2\x_3endpmatrix$ where $x_1,x_2,x_3$ are the three directions towards the the $mathbbR^3$-space.
    – mrtaurho
    Aug 1 at 18:54





    You can interpret this system of equation as the point of intersection within $mathbbR^3$ of the three given functions. For that every single variable represents on direction of the $3$-dimensional space you can just conclude setting the vector x as $beginpmatrixx_1\x_2\x_3endpmatrix$ where $x_1,x_2,x_3$ are the three directions towards the the $mathbbR^3$-space.
    – mrtaurho
    Aug 1 at 18:54











    up vote
    1
    down vote













    basically!



    $
    A = beginpmatrix -2 & 1 & -4 \ 1 & -2 & 0 \ 1 & 1 & -4 endpmatrix
    $
    and $b = beginpmatrix 1 \ -3 \ 0 endpmatrix$ yielding $Ax = b$.






    share|cite|improve this answer

























      up vote
      1
      down vote













      basically!



      $
      A = beginpmatrix -2 & 1 & -4 \ 1 & -2 & 0 \ 1 & 1 & -4 endpmatrix
      $
      and $b = beginpmatrix 1 \ -3 \ 0 endpmatrix$ yielding $Ax = b$.






      share|cite|improve this answer























        up vote
        1
        down vote










        up vote
        1
        down vote









        basically!



        $
        A = beginpmatrix -2 & 1 & -4 \ 1 & -2 & 0 \ 1 & 1 & -4 endpmatrix
        $
        and $b = beginpmatrix 1 \ -3 \ 0 endpmatrix$ yielding $Ax = b$.






        share|cite|improve this answer













        basically!



        $
        A = beginpmatrix -2 & 1 & -4 \ 1 & -2 & 0 \ 1 & 1 & -4 endpmatrix
        $
        and $b = beginpmatrix 1 \ -3 \ 0 endpmatrix$ yielding $Ax = b$.







        share|cite|improve this answer













        share|cite|improve this answer



        share|cite|improve this answer











        answered Aug 1 at 18:22









        pointguard0

        641517




        641517






















             

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