some confusion in upper traingular matrix?











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$1$. What is the dimension of the subspace of all real $n times n$ matrix of upper triangular matrix?



$2$. What is dimension of all real $n times n$ matrix of upper triangular ?



Is both option



$1)$



and



$2)$ having same dimension?



Any hints/solution










share|cite|improve this question




























    up vote
    1
    down vote

    favorite












    $1$. What is the dimension of the subspace of all real $n times n$ matrix of upper triangular matrix?



    $2$. What is dimension of all real $n times n$ matrix of upper triangular ?



    Is both option



    $1)$



    and



    $2)$ having same dimension?



    Any hints/solution










    share|cite|improve this question


























      up vote
      1
      down vote

      favorite









      up vote
      1
      down vote

      favorite











      $1$. What is the dimension of the subspace of all real $n times n$ matrix of upper triangular matrix?



      $2$. What is dimension of all real $n times n$ matrix of upper triangular ?



      Is both option



      $1)$



      and



      $2)$ having same dimension?



      Any hints/solution










      share|cite|improve this question















      $1$. What is the dimension of the subspace of all real $n times n$ matrix of upper triangular matrix?



      $2$. What is dimension of all real $n times n$ matrix of upper triangular ?



      Is both option



      $1)$



      and



      $2)$ having same dimension?



      Any hints/solution







      linear-algebra






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Nov 27 at 15:35









      amWhy

      191k28223439




      191k28223439










      asked Nov 27 at 14:07









      Messi fifa

      50111




      50111






















          2 Answers
          2






          active

          oldest

          votes

















          up vote
          2
          down vote



          accepted










          For 2), let be $S$ the space of upper triangular matrix $M_n(R)$. So the dimension is equal to the elements in that space that can be a base (every matrix with 1 in any single place) so the dimension will be dim($S$)$= n+(n-1)+(n-2)+...+3+2+1 = {n(n+1) over 2 }$; of course it depends on $n$.



          For sure dim($S$) < $n*n$ in this case.
          Every element of this kind can be a base remember!



          For 1), is the same as 2), the "subspace" requirements seems identical to question 2).






          share|cite|improve this answer





















          • .@alessar .is this method same for lower triangular ??
            – Messi fifa
            Nov 27 at 14:24








          • 1




            The matrix is $n*n$, so the dimension is the same; they are simply symmetrical respect the principal diagonal
            – Alessar
            Nov 27 at 14:26








          • 1




            thanks u got its
            – Messi fifa
            Nov 27 at 14:28


















          up vote
          2
          down vote













          HINT



          An upper triangular matrix is defined by $N=frac{n(n+1)}{2}$ elements.






          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
            2
            down vote



            accepted










            For 2), let be $S$ the space of upper triangular matrix $M_n(R)$. So the dimension is equal to the elements in that space that can be a base (every matrix with 1 in any single place) so the dimension will be dim($S$)$= n+(n-1)+(n-2)+...+3+2+1 = {n(n+1) over 2 }$; of course it depends on $n$.



            For sure dim($S$) < $n*n$ in this case.
            Every element of this kind can be a base remember!



            For 1), is the same as 2), the "subspace" requirements seems identical to question 2).






            share|cite|improve this answer





















            • .@alessar .is this method same for lower triangular ??
              – Messi fifa
              Nov 27 at 14:24








            • 1




              The matrix is $n*n$, so the dimension is the same; they are simply symmetrical respect the principal diagonal
              – Alessar
              Nov 27 at 14:26








            • 1




              thanks u got its
              – Messi fifa
              Nov 27 at 14:28















            up vote
            2
            down vote



            accepted










            For 2), let be $S$ the space of upper triangular matrix $M_n(R)$. So the dimension is equal to the elements in that space that can be a base (every matrix with 1 in any single place) so the dimension will be dim($S$)$= n+(n-1)+(n-2)+...+3+2+1 = {n(n+1) over 2 }$; of course it depends on $n$.



            For sure dim($S$) < $n*n$ in this case.
            Every element of this kind can be a base remember!



            For 1), is the same as 2), the "subspace" requirements seems identical to question 2).






            share|cite|improve this answer





















            • .@alessar .is this method same for lower triangular ??
              – Messi fifa
              Nov 27 at 14:24








            • 1




              The matrix is $n*n$, so the dimension is the same; they are simply symmetrical respect the principal diagonal
              – Alessar
              Nov 27 at 14:26








            • 1




              thanks u got its
              – Messi fifa
              Nov 27 at 14:28













            up vote
            2
            down vote



            accepted







            up vote
            2
            down vote



            accepted






            For 2), let be $S$ the space of upper triangular matrix $M_n(R)$. So the dimension is equal to the elements in that space that can be a base (every matrix with 1 in any single place) so the dimension will be dim($S$)$= n+(n-1)+(n-2)+...+3+2+1 = {n(n+1) over 2 }$; of course it depends on $n$.



            For sure dim($S$) < $n*n$ in this case.
            Every element of this kind can be a base remember!



            For 1), is the same as 2), the "subspace" requirements seems identical to question 2).






            share|cite|improve this answer












            For 2), let be $S$ the space of upper triangular matrix $M_n(R)$. So the dimension is equal to the elements in that space that can be a base (every matrix with 1 in any single place) so the dimension will be dim($S$)$= n+(n-1)+(n-2)+...+3+2+1 = {n(n+1) over 2 }$; of course it depends on $n$.



            For sure dim($S$) < $n*n$ in this case.
            Every element of this kind can be a base remember!



            For 1), is the same as 2), the "subspace" requirements seems identical to question 2).







            share|cite|improve this answer












            share|cite|improve this answer



            share|cite|improve this answer










            answered Nov 27 at 14:18









            Alessar

            17213




            17213












            • .@alessar .is this method same for lower triangular ??
              – Messi fifa
              Nov 27 at 14:24








            • 1




              The matrix is $n*n$, so the dimension is the same; they are simply symmetrical respect the principal diagonal
              – Alessar
              Nov 27 at 14:26








            • 1




              thanks u got its
              – Messi fifa
              Nov 27 at 14:28


















            • .@alessar .is this method same for lower triangular ??
              – Messi fifa
              Nov 27 at 14:24








            • 1




              The matrix is $n*n$, so the dimension is the same; they are simply symmetrical respect the principal diagonal
              – Alessar
              Nov 27 at 14:26








            • 1




              thanks u got its
              – Messi fifa
              Nov 27 at 14:28
















            .@alessar .is this method same for lower triangular ??
            – Messi fifa
            Nov 27 at 14:24






            .@alessar .is this method same for lower triangular ??
            – Messi fifa
            Nov 27 at 14:24






            1




            1




            The matrix is $n*n$, so the dimension is the same; they are simply symmetrical respect the principal diagonal
            – Alessar
            Nov 27 at 14:26






            The matrix is $n*n$, so the dimension is the same; they are simply symmetrical respect the principal diagonal
            – Alessar
            Nov 27 at 14:26






            1




            1




            thanks u got its
            – Messi fifa
            Nov 27 at 14:28




            thanks u got its
            – Messi fifa
            Nov 27 at 14:28










            up vote
            2
            down vote













            HINT



            An upper triangular matrix is defined by $N=frac{n(n+1)}{2}$ elements.






            share|cite|improve this answer

























              up vote
              2
              down vote













              HINT



              An upper triangular matrix is defined by $N=frac{n(n+1)}{2}$ elements.






              share|cite|improve this answer























                up vote
                2
                down vote










                up vote
                2
                down vote









                HINT



                An upper triangular matrix is defined by $N=frac{n(n+1)}{2}$ elements.






                share|cite|improve this answer












                HINT



                An upper triangular matrix is defined by $N=frac{n(n+1)}{2}$ elements.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Nov 27 at 14:19









                gimusi

                91.9k84495




                91.9k84495






























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