Proof that $X = left{ A in mathbb R^{6,5} : V subset ker(A) right}$ is linear subspace and find its $dim$












2












$begingroup$


Proof that if $dim V = 3 $ then $X = left{ A in mathbb R^{6,5} : V subset ker(A) right}$ is linear subspace and find its $dim$



What I've done



I think that I have done proof.
$ forall vec{v} in V. Avec{v} = 0 $ and $Bvec{v}=0$

but from property of the matrix product it follows that:
$$ Avec{v} + Bvec{v} = (A+B)vec{v} $$



Moreover if $Avec{x}=0$ then $(alpha A)vec{x} =0$ and in to other side too. So ok.



My problem



But how in use of given informations find its dimension? My scribbles do not lead to anything.










share|cite|improve this question











$endgroup$












  • $begingroup$
    What do you denote $Bbb R^{6,5}$?
    $endgroup$
    – Bernard
    Dec 31 '18 at 17:23












  • $begingroup$
    Sorry, I used to write RR but there it does not work I didn't know how to write it. But now I will remember, thanks
    $endgroup$
    – VirtualUser
    Dec 31 '18 at 17:33
















2












$begingroup$


Proof that if $dim V = 3 $ then $X = left{ A in mathbb R^{6,5} : V subset ker(A) right}$ is linear subspace and find its $dim$



What I've done



I think that I have done proof.
$ forall vec{v} in V. Avec{v} = 0 $ and $Bvec{v}=0$

but from property of the matrix product it follows that:
$$ Avec{v} + Bvec{v} = (A+B)vec{v} $$



Moreover if $Avec{x}=0$ then $(alpha A)vec{x} =0$ and in to other side too. So ok.



My problem



But how in use of given informations find its dimension? My scribbles do not lead to anything.










share|cite|improve this question











$endgroup$












  • $begingroup$
    What do you denote $Bbb R^{6,5}$?
    $endgroup$
    – Bernard
    Dec 31 '18 at 17:23












  • $begingroup$
    Sorry, I used to write RR but there it does not work I didn't know how to write it. But now I will remember, thanks
    $endgroup$
    – VirtualUser
    Dec 31 '18 at 17:33














2












2








2





$begingroup$


Proof that if $dim V = 3 $ then $X = left{ A in mathbb R^{6,5} : V subset ker(A) right}$ is linear subspace and find its $dim$



What I've done



I think that I have done proof.
$ forall vec{v} in V. Avec{v} = 0 $ and $Bvec{v}=0$

but from property of the matrix product it follows that:
$$ Avec{v} + Bvec{v} = (A+B)vec{v} $$



Moreover if $Avec{x}=0$ then $(alpha A)vec{x} =0$ and in to other side too. So ok.



My problem



But how in use of given informations find its dimension? My scribbles do not lead to anything.










share|cite|improve this question











$endgroup$




Proof that if $dim V = 3 $ then $X = left{ A in mathbb R^{6,5} : V subset ker(A) right}$ is linear subspace and find its $dim$



What I've done



I think that I have done proof.
$ forall vec{v} in V. Avec{v} = 0 $ and $Bvec{v}=0$

but from property of the matrix product it follows that:
$$ Avec{v} + Bvec{v} = (A+B)vec{v} $$



Moreover if $Avec{x}=0$ then $(alpha A)vec{x} =0$ and in to other side too. So ok.



My problem



But how in use of given informations find its dimension? My scribbles do not lead to anything.







linear-algebra vector-spaces






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Dec 31 '18 at 17:21









Bernard

119k639112




119k639112










asked Dec 31 '18 at 17:12









VirtualUserVirtualUser

58912




58912












  • $begingroup$
    What do you denote $Bbb R^{6,5}$?
    $endgroup$
    – Bernard
    Dec 31 '18 at 17:23












  • $begingroup$
    Sorry, I used to write RR but there it does not work I didn't know how to write it. But now I will remember, thanks
    $endgroup$
    – VirtualUser
    Dec 31 '18 at 17:33


















  • $begingroup$
    What do you denote $Bbb R^{6,5}$?
    $endgroup$
    – Bernard
    Dec 31 '18 at 17:23












  • $begingroup$
    Sorry, I used to write RR but there it does not work I didn't know how to write it. But now I will remember, thanks
    $endgroup$
    – VirtualUser
    Dec 31 '18 at 17:33
















$begingroup$
What do you denote $Bbb R^{6,5}$?
$endgroup$
– Bernard
Dec 31 '18 at 17:23






$begingroup$
What do you denote $Bbb R^{6,5}$?
$endgroup$
– Bernard
Dec 31 '18 at 17:23














$begingroup$
Sorry, I used to write RR but there it does not work I didn't know how to write it. But now I will remember, thanks
$endgroup$
– VirtualUser
Dec 31 '18 at 17:33




$begingroup$
Sorry, I used to write RR but there it does not work I didn't know how to write it. But now I will remember, thanks
$endgroup$
– VirtualUser
Dec 31 '18 at 17:33










2 Answers
2






active

oldest

votes


















1












$begingroup$

$mathbb R^{6,5}$ is a linear space of dimension $6 times 5=30$.



If $(v_1, v_2, v_3)$ (with $v_i in mathbb R^5$) is a basis of $V$. You have



$$X = {A in mathbb R^{6,5} ; A.v_1=A.v_2=A.v_3=0}.$$



It means that you're imposing $3 times 6 = 18$ independent conditions in the dual space $left(mathbb R^{6,5}right)^vee$. Hence $dim X = 30 -18=12$.



Another proof not using the dual space



Without loss of generality, you can suppose that $(v_1, dots, v_5)$ is a basis of $mathcal V = mathbb R^5$ where $(v_1, v_2,v_3)$ is a basis of $V$. And that $(v_1^prime, dots, v_6^prime)$ is a basis of $mathcal V^prime=mathbb R^6$.



For $A =(a_{ij}) in X$ expressed in those basis, you must have $$a_{11} =dots =a_{61}=a_{12}=dots=a_{62}=a_{13}=dots=a_{63}=0$$ as $V subseteq ker A$.
If we denote $E_{ij}$ the matrix with coefficient $i,j$ equal to $1$ and the others vanishing, $(E_{14}, dots, E_{64}, E_{15}, dots, E_{65})$ is a basis of $X$. Proving that the dimension of that linear subspace is equal to $12$.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    I don't understand this notation: $A.v_1=A.v_2=A.v_3=0$. Does $A.v_{i} $ means $i$ column? I suspect that these are not the same vectors as the vectors from base $V$?
    $endgroup$
    – VirtualUser
    Dec 31 '18 at 17:47










  • $begingroup$
    For a vector $v in V$ (with 5 coordinates) $A.v$ means the image by $A$ of vector $v$. $A.v$ is a vector with 6 coordinates.
    $endgroup$
    – mathcounterexamples.net
    Dec 31 '18 at 17:49










  • $begingroup$
    Can it be done without dual space? I haven't got this on lecture and probably I can't use that
    $endgroup$
    – VirtualUser
    Jan 2 at 19:12












  • $begingroup$
    What are the key theorems of your lecture?
    $endgroup$
    – mathcounterexamples.net
    Jan 2 at 20:35










  • $begingroup$
    image, kernel, rank, basis of linear space, sum of linear spaces linear independence and linear combinations
    $endgroup$
    – VirtualUser
    Jan 2 at 20:39



















0












$begingroup$

Since $Vsubsetker(A)forall Ain X$, the rows of $A$ are orthogonal to all vectors in $V$ and thus belong to $V^perp$, which has dimension $2$. Each row vector of $A$ is the linear combination of the two basis vectors $v_1,v_2$ of $V^perp$.



$$A=begin{bmatrix}a_{11}v_1^T+a_{12}v_2^T\a_{21}v_1^T+a_{22}v_2^T\vdots\a_{61}v_1^T+a_{62}v_2^Tend{bmatrix}=a_{11}begin{bmatrix}v_1^T\0\vdots\0end{bmatrix}+a_{12}begin{bmatrix}v_2^T\0\vdots\0end{bmatrix}+a_{21}begin{bmatrix}0\v_1^T\vdots\0end{bmatrix}+...+a_{62}begin{bmatrix}0\0\vdots\v_2^Tend{bmatrix}$$



Thus, $X$ has $12$ basis vectors.






share|cite|improve this answer









$endgroup$













    Your Answer





    StackExchange.ifUsing("editor", function () {
    return StackExchange.using("mathjaxEditing", function () {
    StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
    StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
    });
    });
    }, "mathjax-editing");

    StackExchange.ready(function() {
    var channelOptions = {
    tags: "".split(" "),
    id: "69"
    };
    initTagRenderer("".split(" "), "".split(" "), channelOptions);

    StackExchange.using("externalEditor", function() {
    // Have to fire editor after snippets, if snippets enabled
    if (StackExchange.settings.snippets.snippetsEnabled) {
    StackExchange.using("snippets", function() {
    createEditor();
    });
    }
    else {
    createEditor();
    }
    });

    function createEditor() {
    StackExchange.prepareEditor({
    heartbeatType: 'answer',
    autoActivateHeartbeat: false,
    convertImagesToLinks: true,
    noModals: true,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: 10,
    bindNavPrevention: true,
    postfix: "",
    imageUploader: {
    brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
    contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
    allowUrls: true
    },
    noCode: true, onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    });


    }
    });














    draft saved

    draft discarded


















    StackExchange.ready(
    function () {
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3057870%2fproof-that-x-left-a-in-mathbb-r6-5-v-subset-kera-right-is-l%23new-answer', 'question_page');
    }
    );

    Post as a guest















    Required, but never shown

























    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    1












    $begingroup$

    $mathbb R^{6,5}$ is a linear space of dimension $6 times 5=30$.



    If $(v_1, v_2, v_3)$ (with $v_i in mathbb R^5$) is a basis of $V$. You have



    $$X = {A in mathbb R^{6,5} ; A.v_1=A.v_2=A.v_3=0}.$$



    It means that you're imposing $3 times 6 = 18$ independent conditions in the dual space $left(mathbb R^{6,5}right)^vee$. Hence $dim X = 30 -18=12$.



    Another proof not using the dual space



    Without loss of generality, you can suppose that $(v_1, dots, v_5)$ is a basis of $mathcal V = mathbb R^5$ where $(v_1, v_2,v_3)$ is a basis of $V$. And that $(v_1^prime, dots, v_6^prime)$ is a basis of $mathcal V^prime=mathbb R^6$.



    For $A =(a_{ij}) in X$ expressed in those basis, you must have $$a_{11} =dots =a_{61}=a_{12}=dots=a_{62}=a_{13}=dots=a_{63}=0$$ as $V subseteq ker A$.
    If we denote $E_{ij}$ the matrix with coefficient $i,j$ equal to $1$ and the others vanishing, $(E_{14}, dots, E_{64}, E_{15}, dots, E_{65})$ is a basis of $X$. Proving that the dimension of that linear subspace is equal to $12$.






    share|cite|improve this answer











    $endgroup$













    • $begingroup$
      I don't understand this notation: $A.v_1=A.v_2=A.v_3=0$. Does $A.v_{i} $ means $i$ column? I suspect that these are not the same vectors as the vectors from base $V$?
      $endgroup$
      – VirtualUser
      Dec 31 '18 at 17:47










    • $begingroup$
      For a vector $v in V$ (with 5 coordinates) $A.v$ means the image by $A$ of vector $v$. $A.v$ is a vector with 6 coordinates.
      $endgroup$
      – mathcounterexamples.net
      Dec 31 '18 at 17:49










    • $begingroup$
      Can it be done without dual space? I haven't got this on lecture and probably I can't use that
      $endgroup$
      – VirtualUser
      Jan 2 at 19:12












    • $begingroup$
      What are the key theorems of your lecture?
      $endgroup$
      – mathcounterexamples.net
      Jan 2 at 20:35










    • $begingroup$
      image, kernel, rank, basis of linear space, sum of linear spaces linear independence and linear combinations
      $endgroup$
      – VirtualUser
      Jan 2 at 20:39
















    1












    $begingroup$

    $mathbb R^{6,5}$ is a linear space of dimension $6 times 5=30$.



    If $(v_1, v_2, v_3)$ (with $v_i in mathbb R^5$) is a basis of $V$. You have



    $$X = {A in mathbb R^{6,5} ; A.v_1=A.v_2=A.v_3=0}.$$



    It means that you're imposing $3 times 6 = 18$ independent conditions in the dual space $left(mathbb R^{6,5}right)^vee$. Hence $dim X = 30 -18=12$.



    Another proof not using the dual space



    Without loss of generality, you can suppose that $(v_1, dots, v_5)$ is a basis of $mathcal V = mathbb R^5$ where $(v_1, v_2,v_3)$ is a basis of $V$. And that $(v_1^prime, dots, v_6^prime)$ is a basis of $mathcal V^prime=mathbb R^6$.



    For $A =(a_{ij}) in X$ expressed in those basis, you must have $$a_{11} =dots =a_{61}=a_{12}=dots=a_{62}=a_{13}=dots=a_{63}=0$$ as $V subseteq ker A$.
    If we denote $E_{ij}$ the matrix with coefficient $i,j$ equal to $1$ and the others vanishing, $(E_{14}, dots, E_{64}, E_{15}, dots, E_{65})$ is a basis of $X$. Proving that the dimension of that linear subspace is equal to $12$.






    share|cite|improve this answer











    $endgroup$













    • $begingroup$
      I don't understand this notation: $A.v_1=A.v_2=A.v_3=0$. Does $A.v_{i} $ means $i$ column? I suspect that these are not the same vectors as the vectors from base $V$?
      $endgroup$
      – VirtualUser
      Dec 31 '18 at 17:47










    • $begingroup$
      For a vector $v in V$ (with 5 coordinates) $A.v$ means the image by $A$ of vector $v$. $A.v$ is a vector with 6 coordinates.
      $endgroup$
      – mathcounterexamples.net
      Dec 31 '18 at 17:49










    • $begingroup$
      Can it be done without dual space? I haven't got this on lecture and probably I can't use that
      $endgroup$
      – VirtualUser
      Jan 2 at 19:12












    • $begingroup$
      What are the key theorems of your lecture?
      $endgroup$
      – mathcounterexamples.net
      Jan 2 at 20:35










    • $begingroup$
      image, kernel, rank, basis of linear space, sum of linear spaces linear independence and linear combinations
      $endgroup$
      – VirtualUser
      Jan 2 at 20:39














    1












    1








    1





    $begingroup$

    $mathbb R^{6,5}$ is a linear space of dimension $6 times 5=30$.



    If $(v_1, v_2, v_3)$ (with $v_i in mathbb R^5$) is a basis of $V$. You have



    $$X = {A in mathbb R^{6,5} ; A.v_1=A.v_2=A.v_3=0}.$$



    It means that you're imposing $3 times 6 = 18$ independent conditions in the dual space $left(mathbb R^{6,5}right)^vee$. Hence $dim X = 30 -18=12$.



    Another proof not using the dual space



    Without loss of generality, you can suppose that $(v_1, dots, v_5)$ is a basis of $mathcal V = mathbb R^5$ where $(v_1, v_2,v_3)$ is a basis of $V$. And that $(v_1^prime, dots, v_6^prime)$ is a basis of $mathcal V^prime=mathbb R^6$.



    For $A =(a_{ij}) in X$ expressed in those basis, you must have $$a_{11} =dots =a_{61}=a_{12}=dots=a_{62}=a_{13}=dots=a_{63}=0$$ as $V subseteq ker A$.
    If we denote $E_{ij}$ the matrix with coefficient $i,j$ equal to $1$ and the others vanishing, $(E_{14}, dots, E_{64}, E_{15}, dots, E_{65})$ is a basis of $X$. Proving that the dimension of that linear subspace is equal to $12$.






    share|cite|improve this answer











    $endgroup$



    $mathbb R^{6,5}$ is a linear space of dimension $6 times 5=30$.



    If $(v_1, v_2, v_3)$ (with $v_i in mathbb R^5$) is a basis of $V$. You have



    $$X = {A in mathbb R^{6,5} ; A.v_1=A.v_2=A.v_3=0}.$$



    It means that you're imposing $3 times 6 = 18$ independent conditions in the dual space $left(mathbb R^{6,5}right)^vee$. Hence $dim X = 30 -18=12$.



    Another proof not using the dual space



    Without loss of generality, you can suppose that $(v_1, dots, v_5)$ is a basis of $mathcal V = mathbb R^5$ where $(v_1, v_2,v_3)$ is a basis of $V$. And that $(v_1^prime, dots, v_6^prime)$ is a basis of $mathcal V^prime=mathbb R^6$.



    For $A =(a_{ij}) in X$ expressed in those basis, you must have $$a_{11} =dots =a_{61}=a_{12}=dots=a_{62}=a_{13}=dots=a_{63}=0$$ as $V subseteq ker A$.
    If we denote $E_{ij}$ the matrix with coefficient $i,j$ equal to $1$ and the others vanishing, $(E_{14}, dots, E_{64}, E_{15}, dots, E_{65})$ is a basis of $X$. Proving that the dimension of that linear subspace is equal to $12$.







    share|cite|improve this answer














    share|cite|improve this answer



    share|cite|improve this answer








    edited Jan 3 at 5:51

























    answered Dec 31 '18 at 17:28









    mathcounterexamples.netmathcounterexamples.net

    25.3k21953




    25.3k21953












    • $begingroup$
      I don't understand this notation: $A.v_1=A.v_2=A.v_3=0$. Does $A.v_{i} $ means $i$ column? I suspect that these are not the same vectors as the vectors from base $V$?
      $endgroup$
      – VirtualUser
      Dec 31 '18 at 17:47










    • $begingroup$
      For a vector $v in V$ (with 5 coordinates) $A.v$ means the image by $A$ of vector $v$. $A.v$ is a vector with 6 coordinates.
      $endgroup$
      – mathcounterexamples.net
      Dec 31 '18 at 17:49










    • $begingroup$
      Can it be done without dual space? I haven't got this on lecture and probably I can't use that
      $endgroup$
      – VirtualUser
      Jan 2 at 19:12












    • $begingroup$
      What are the key theorems of your lecture?
      $endgroup$
      – mathcounterexamples.net
      Jan 2 at 20:35










    • $begingroup$
      image, kernel, rank, basis of linear space, sum of linear spaces linear independence and linear combinations
      $endgroup$
      – VirtualUser
      Jan 2 at 20:39


















    • $begingroup$
      I don't understand this notation: $A.v_1=A.v_2=A.v_3=0$. Does $A.v_{i} $ means $i$ column? I suspect that these are not the same vectors as the vectors from base $V$?
      $endgroup$
      – VirtualUser
      Dec 31 '18 at 17:47










    • $begingroup$
      For a vector $v in V$ (with 5 coordinates) $A.v$ means the image by $A$ of vector $v$. $A.v$ is a vector with 6 coordinates.
      $endgroup$
      – mathcounterexamples.net
      Dec 31 '18 at 17:49










    • $begingroup$
      Can it be done without dual space? I haven't got this on lecture and probably I can't use that
      $endgroup$
      – VirtualUser
      Jan 2 at 19:12












    • $begingroup$
      What are the key theorems of your lecture?
      $endgroup$
      – mathcounterexamples.net
      Jan 2 at 20:35










    • $begingroup$
      image, kernel, rank, basis of linear space, sum of linear spaces linear independence and linear combinations
      $endgroup$
      – VirtualUser
      Jan 2 at 20:39
















    $begingroup$
    I don't understand this notation: $A.v_1=A.v_2=A.v_3=0$. Does $A.v_{i} $ means $i$ column? I suspect that these are not the same vectors as the vectors from base $V$?
    $endgroup$
    – VirtualUser
    Dec 31 '18 at 17:47




    $begingroup$
    I don't understand this notation: $A.v_1=A.v_2=A.v_3=0$. Does $A.v_{i} $ means $i$ column? I suspect that these are not the same vectors as the vectors from base $V$?
    $endgroup$
    – VirtualUser
    Dec 31 '18 at 17:47












    $begingroup$
    For a vector $v in V$ (with 5 coordinates) $A.v$ means the image by $A$ of vector $v$. $A.v$ is a vector with 6 coordinates.
    $endgroup$
    – mathcounterexamples.net
    Dec 31 '18 at 17:49




    $begingroup$
    For a vector $v in V$ (with 5 coordinates) $A.v$ means the image by $A$ of vector $v$. $A.v$ is a vector with 6 coordinates.
    $endgroup$
    – mathcounterexamples.net
    Dec 31 '18 at 17:49












    $begingroup$
    Can it be done without dual space? I haven't got this on lecture and probably I can't use that
    $endgroup$
    – VirtualUser
    Jan 2 at 19:12






    $begingroup$
    Can it be done without dual space? I haven't got this on lecture and probably I can't use that
    $endgroup$
    – VirtualUser
    Jan 2 at 19:12














    $begingroup$
    What are the key theorems of your lecture?
    $endgroup$
    – mathcounterexamples.net
    Jan 2 at 20:35




    $begingroup$
    What are the key theorems of your lecture?
    $endgroup$
    – mathcounterexamples.net
    Jan 2 at 20:35












    $begingroup$
    image, kernel, rank, basis of linear space, sum of linear spaces linear independence and linear combinations
    $endgroup$
    – VirtualUser
    Jan 2 at 20:39




    $begingroup$
    image, kernel, rank, basis of linear space, sum of linear spaces linear independence and linear combinations
    $endgroup$
    – VirtualUser
    Jan 2 at 20:39











    0












    $begingroup$

    Since $Vsubsetker(A)forall Ain X$, the rows of $A$ are orthogonal to all vectors in $V$ and thus belong to $V^perp$, which has dimension $2$. Each row vector of $A$ is the linear combination of the two basis vectors $v_1,v_2$ of $V^perp$.



    $$A=begin{bmatrix}a_{11}v_1^T+a_{12}v_2^T\a_{21}v_1^T+a_{22}v_2^T\vdots\a_{61}v_1^T+a_{62}v_2^Tend{bmatrix}=a_{11}begin{bmatrix}v_1^T\0\vdots\0end{bmatrix}+a_{12}begin{bmatrix}v_2^T\0\vdots\0end{bmatrix}+a_{21}begin{bmatrix}0\v_1^T\vdots\0end{bmatrix}+...+a_{62}begin{bmatrix}0\0\vdots\v_2^Tend{bmatrix}$$



    Thus, $X$ has $12$ basis vectors.






    share|cite|improve this answer









    $endgroup$


















      0












      $begingroup$

      Since $Vsubsetker(A)forall Ain X$, the rows of $A$ are orthogonal to all vectors in $V$ and thus belong to $V^perp$, which has dimension $2$. Each row vector of $A$ is the linear combination of the two basis vectors $v_1,v_2$ of $V^perp$.



      $$A=begin{bmatrix}a_{11}v_1^T+a_{12}v_2^T\a_{21}v_1^T+a_{22}v_2^T\vdots\a_{61}v_1^T+a_{62}v_2^Tend{bmatrix}=a_{11}begin{bmatrix}v_1^T\0\vdots\0end{bmatrix}+a_{12}begin{bmatrix}v_2^T\0\vdots\0end{bmatrix}+a_{21}begin{bmatrix}0\v_1^T\vdots\0end{bmatrix}+...+a_{62}begin{bmatrix}0\0\vdots\v_2^Tend{bmatrix}$$



      Thus, $X$ has $12$ basis vectors.






      share|cite|improve this answer









      $endgroup$
















        0












        0








        0





        $begingroup$

        Since $Vsubsetker(A)forall Ain X$, the rows of $A$ are orthogonal to all vectors in $V$ and thus belong to $V^perp$, which has dimension $2$. Each row vector of $A$ is the linear combination of the two basis vectors $v_1,v_2$ of $V^perp$.



        $$A=begin{bmatrix}a_{11}v_1^T+a_{12}v_2^T\a_{21}v_1^T+a_{22}v_2^T\vdots\a_{61}v_1^T+a_{62}v_2^Tend{bmatrix}=a_{11}begin{bmatrix}v_1^T\0\vdots\0end{bmatrix}+a_{12}begin{bmatrix}v_2^T\0\vdots\0end{bmatrix}+a_{21}begin{bmatrix}0\v_1^T\vdots\0end{bmatrix}+...+a_{62}begin{bmatrix}0\0\vdots\v_2^Tend{bmatrix}$$



        Thus, $X$ has $12$ basis vectors.






        share|cite|improve this answer









        $endgroup$



        Since $Vsubsetker(A)forall Ain X$, the rows of $A$ are orthogonal to all vectors in $V$ and thus belong to $V^perp$, which has dimension $2$. Each row vector of $A$ is the linear combination of the two basis vectors $v_1,v_2$ of $V^perp$.



        $$A=begin{bmatrix}a_{11}v_1^T+a_{12}v_2^T\a_{21}v_1^T+a_{22}v_2^T\vdots\a_{61}v_1^T+a_{62}v_2^Tend{bmatrix}=a_{11}begin{bmatrix}v_1^T\0\vdots\0end{bmatrix}+a_{12}begin{bmatrix}v_2^T\0\vdots\0end{bmatrix}+a_{21}begin{bmatrix}0\v_1^T\vdots\0end{bmatrix}+...+a_{62}begin{bmatrix}0\0\vdots\v_2^Tend{bmatrix}$$



        Thus, $X$ has $12$ basis vectors.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 1 at 12:40









        Shubham JohriShubham Johri

        4,666717




        4,666717






























            draft saved

            draft discarded




















































            Thanks for contributing an answer to Mathematics Stack Exchange!


            • Please be sure to answer the question. Provide details and share your research!

            But avoid



            • Asking for help, clarification, or responding to other answers.

            • Making statements based on opinion; back them up with references or personal experience.


            Use MathJax to format equations. MathJax reference.


            To learn more, see our tips on writing great answers.




            draft saved


            draft discarded














            StackExchange.ready(
            function () {
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3057870%2fproof-that-x-left-a-in-mathbb-r6-5-v-subset-kera-right-is-l%23new-answer', 'question_page');
            }
            );

            Post as a guest















            Required, but never shown





















































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown

































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown







            Popular posts from this blog

            'app-layout' is not a known element: how to share Component with different Modules

            android studio warns about leanback feature tag usage required on manifest while using Unity exported app?

            WPF add header to Image with URL pettitions [duplicate]