Bilinear form with parameter [closed]

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I have a bilinear form such that the associate matrix is $ A=left(beginmatrix0&0&k\
0&k&0\
k&0&0\
endmatrixright)$.
$,$ Does exist a $k$ such that $F_k((e_1+e_2+e_3),(e_1+e_2+e_3))=4$



I don't understand how can I start!







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closed as off-topic by Travis, Strants, José Carlos Santos, Adrian Keister, user223391 Jul 20 at 1:33


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Travis, Strants, José Carlos Santos, Adrian Keister, Community
If this question can be reworded to fit the rules in the help center, please edit the question.












  • How is $F_k$ defined?
    – José Carlos Santos
    Jul 16 at 16:05










  • $xz'+yy'+zx'$ right?
    – Roberto De La Fuente
    Jul 16 at 16:07














up vote
0
down vote

favorite












I have a bilinear form such that the associate matrix is $ A=left(beginmatrix0&0&k\
0&k&0\
k&0&0\
endmatrixright)$.
$,$ Does exist a $k$ such that $F_k((e_1+e_2+e_3),(e_1+e_2+e_3))=4$



I don't understand how can I start!







share|cite|improve this question













closed as off-topic by Travis, Strants, José Carlos Santos, Adrian Keister, user223391 Jul 20 at 1:33


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Travis, Strants, José Carlos Santos, Adrian Keister, Community
If this question can be reworded to fit the rules in the help center, please edit the question.












  • How is $F_k$ defined?
    – José Carlos Santos
    Jul 16 at 16:05










  • $xz'+yy'+zx'$ right?
    – Roberto De La Fuente
    Jul 16 at 16:07












up vote
0
down vote

favorite









up vote
0
down vote

favorite











I have a bilinear form such that the associate matrix is $ A=left(beginmatrix0&0&k\
0&k&0\
k&0&0\
endmatrixright)$.
$,$ Does exist a $k$ such that $F_k((e_1+e_2+e_3),(e_1+e_2+e_3))=4$



I don't understand how can I start!







share|cite|improve this question













I have a bilinear form such that the associate matrix is $ A=left(beginmatrix0&0&k\
0&k&0\
k&0&0\
endmatrixright)$.
$,$ Does exist a $k$ such that $F_k((e_1+e_2+e_3),(e_1+e_2+e_3))=4$



I don't understand how can I start!









share|cite|improve this question












share|cite|improve this question




share|cite|improve this question








edited Jul 16 at 16:10









Ivo Terek

43.9k949134




43.9k949134









asked Jul 16 at 15:59









Roberto De La Fuente

417




417




closed as off-topic by Travis, Strants, José Carlos Santos, Adrian Keister, user223391 Jul 20 at 1:33


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Travis, Strants, José Carlos Santos, Adrian Keister, Community
If this question can be reworded to fit the rules in the help center, please edit the question.




closed as off-topic by Travis, Strants, José Carlos Santos, Adrian Keister, user223391 Jul 20 at 1:33


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Travis, Strants, José Carlos Santos, Adrian Keister, Community
If this question can be reworded to fit the rules in the help center, please edit the question.











  • How is $F_k$ defined?
    – José Carlos Santos
    Jul 16 at 16:05










  • $xz'+yy'+zx'$ right?
    – Roberto De La Fuente
    Jul 16 at 16:07
















  • How is $F_k$ defined?
    – José Carlos Santos
    Jul 16 at 16:05










  • $xz'+yy'+zx'$ right?
    – Roberto De La Fuente
    Jul 16 at 16:07















How is $F_k$ defined?
– José Carlos Santos
Jul 16 at 16:05




How is $F_k$ defined?
– José Carlos Santos
Jul 16 at 16:05












$xz'+yy'+zx'$ right?
– Roberto De La Fuente
Jul 16 at 16:07




$xz'+yy'+zx'$ right?
– Roberto De La Fuente
Jul 16 at 16:07










1 Answer
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up vote
1
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You have that $F_k(vecx,vecy) = vecx^top A vecy$, so $$beginalign F_k((1,1,1),(1,1,1)) &= beginpmatrix 1 & 1 & 1endpmatrix beginpmatrix 0 & 0 & k \ 0 & k & 0 \ k & 0 & 0endpmatrix beginpmatrix 1 \ 1 \ 1 endpmatrix \ &= beginpmatrix 1 & 1 & 1endpmatrix beginpmatrix k \ k \ k endpmatrix \ &= 3kendalign$$So $k = 4/3$ fits the bill.






share|cite|improve this answer




























    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    1
    down vote



    accepted










    You have that $F_k(vecx,vecy) = vecx^top A vecy$, so $$beginalign F_k((1,1,1),(1,1,1)) &= beginpmatrix 1 & 1 & 1endpmatrix beginpmatrix 0 & 0 & k \ 0 & k & 0 \ k & 0 & 0endpmatrix beginpmatrix 1 \ 1 \ 1 endpmatrix \ &= beginpmatrix 1 & 1 & 1endpmatrix beginpmatrix k \ k \ k endpmatrix \ &= 3kendalign$$So $k = 4/3$ fits the bill.






    share|cite|improve this answer

























      up vote
      1
      down vote



      accepted










      You have that $F_k(vecx,vecy) = vecx^top A vecy$, so $$beginalign F_k((1,1,1),(1,1,1)) &= beginpmatrix 1 & 1 & 1endpmatrix beginpmatrix 0 & 0 & k \ 0 & k & 0 \ k & 0 & 0endpmatrix beginpmatrix 1 \ 1 \ 1 endpmatrix \ &= beginpmatrix 1 & 1 & 1endpmatrix beginpmatrix k \ k \ k endpmatrix \ &= 3kendalign$$So $k = 4/3$ fits the bill.






      share|cite|improve this answer























        up vote
        1
        down vote



        accepted







        up vote
        1
        down vote



        accepted






        You have that $F_k(vecx,vecy) = vecx^top A vecy$, so $$beginalign F_k((1,1,1),(1,1,1)) &= beginpmatrix 1 & 1 & 1endpmatrix beginpmatrix 0 & 0 & k \ 0 & k & 0 \ k & 0 & 0endpmatrix beginpmatrix 1 \ 1 \ 1 endpmatrix \ &= beginpmatrix 1 & 1 & 1endpmatrix beginpmatrix k \ k \ k endpmatrix \ &= 3kendalign$$So $k = 4/3$ fits the bill.






        share|cite|improve this answer













        You have that $F_k(vecx,vecy) = vecx^top A vecy$, so $$beginalign F_k((1,1,1),(1,1,1)) &= beginpmatrix 1 & 1 & 1endpmatrix beginpmatrix 0 & 0 & k \ 0 & k & 0 \ k & 0 & 0endpmatrix beginpmatrix 1 \ 1 \ 1 endpmatrix \ &= beginpmatrix 1 & 1 & 1endpmatrix beginpmatrix k \ k \ k endpmatrix \ &= 3kendalign$$So $k = 4/3$ fits the bill.







        share|cite|improve this answer













        share|cite|improve this answer



        share|cite|improve this answer











        answered Jul 16 at 16:09









        Ivo Terek

        43.9k949134




        43.9k949134












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