Showing $T^{-1} = T^*$ where T is matrix of normalized eigenvectors of Hermitian matrix












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Let A be an nxn Hermitian matrix with n distinct eigenvalues and T be the matrix whose columns are normalized eigenvectors of A. I want to show that $T^{-1} = T^*$.



I know that the eigenvectors of A are mutually orthogonal, and since they are normalized, then they are orthonormal. Where do I proceed in showing that $T^{-1} = T^*$? Thanks.










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  • $begingroup$
    Compute $TT^*$. Write $T = [t_1 t_2 cdots t_n]$.
    $endgroup$
    – xbh
    Dec 5 '18 at 3:01
















1












$begingroup$


Let A be an nxn Hermitian matrix with n distinct eigenvalues and T be the matrix whose columns are normalized eigenvectors of A. I want to show that $T^{-1} = T^*$.



I know that the eigenvectors of A are mutually orthogonal, and since they are normalized, then they are orthonormal. Where do I proceed in showing that $T^{-1} = T^*$? Thanks.










share|cite|improve this question









$endgroup$












  • $begingroup$
    Compute $TT^*$. Write $T = [t_1 t_2 cdots t_n]$.
    $endgroup$
    – xbh
    Dec 5 '18 at 3:01














1












1








1





$begingroup$


Let A be an nxn Hermitian matrix with n distinct eigenvalues and T be the matrix whose columns are normalized eigenvectors of A. I want to show that $T^{-1} = T^*$.



I know that the eigenvectors of A are mutually orthogonal, and since they are normalized, then they are orthonormal. Where do I proceed in showing that $T^{-1} = T^*$? Thanks.










share|cite|improve this question









$endgroup$




Let A be an nxn Hermitian matrix with n distinct eigenvalues and T be the matrix whose columns are normalized eigenvectors of A. I want to show that $T^{-1} = T^*$.



I know that the eigenvectors of A are mutually orthogonal, and since they are normalized, then they are orthonormal. Where do I proceed in showing that $T^{-1} = T^*$? Thanks.







linear-algebra






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asked Dec 5 '18 at 2:57









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  • $begingroup$
    Compute $TT^*$. Write $T = [t_1 t_2 cdots t_n]$.
    $endgroup$
    – xbh
    Dec 5 '18 at 3:01


















  • $begingroup$
    Compute $TT^*$. Write $T = [t_1 t_2 cdots t_n]$.
    $endgroup$
    – xbh
    Dec 5 '18 at 3:01
















$begingroup$
Compute $TT^*$. Write $T = [t_1 t_2 cdots t_n]$.
$endgroup$
– xbh
Dec 5 '18 at 3:01




$begingroup$
Compute $TT^*$. Write $T = [t_1 t_2 cdots t_n]$.
$endgroup$
– xbh
Dec 5 '18 at 3:01










1 Answer
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$begingroup$

Proof.



Let $T = begin{bmatrix}t_1 & cdots & t_n end{bmatrix}$, where $t_j$'s are $ntimes 1$ column matrices. Since $A$ is Hermitian with $n$ distinct eigenvalues, and $t_j$'s are normalized, ${t_j}_1^n$ satisfies $t_j^* t_k = delta_{j,k}$, thus
$$
T^* T = [t_j^* t_k]_{(j,k)=(1,1)}^{(n,n)} = [delta_{j,k}] = I.
$$






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    1 Answer
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    1 Answer
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    $begingroup$

    Proof.



    Let $T = begin{bmatrix}t_1 & cdots & t_n end{bmatrix}$, where $t_j$'s are $ntimes 1$ column matrices. Since $A$ is Hermitian with $n$ distinct eigenvalues, and $t_j$'s are normalized, ${t_j}_1^n$ satisfies $t_j^* t_k = delta_{j,k}$, thus
    $$
    T^* T = [t_j^* t_k]_{(j,k)=(1,1)}^{(n,n)} = [delta_{j,k}] = I.
    $$






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      0












      $begingroup$

      Proof.



      Let $T = begin{bmatrix}t_1 & cdots & t_n end{bmatrix}$, where $t_j$'s are $ntimes 1$ column matrices. Since $A$ is Hermitian with $n$ distinct eigenvalues, and $t_j$'s are normalized, ${t_j}_1^n$ satisfies $t_j^* t_k = delta_{j,k}$, thus
      $$
      T^* T = [t_j^* t_k]_{(j,k)=(1,1)}^{(n,n)} = [delta_{j,k}] = I.
      $$






      share|cite|improve this answer









      $endgroup$
















        0












        0








        0





        $begingroup$

        Proof.



        Let $T = begin{bmatrix}t_1 & cdots & t_n end{bmatrix}$, where $t_j$'s are $ntimes 1$ column matrices. Since $A$ is Hermitian with $n$ distinct eigenvalues, and $t_j$'s are normalized, ${t_j}_1^n$ satisfies $t_j^* t_k = delta_{j,k}$, thus
        $$
        T^* T = [t_j^* t_k]_{(j,k)=(1,1)}^{(n,n)} = [delta_{j,k}] = I.
        $$






        share|cite|improve this answer









        $endgroup$



        Proof.



        Let $T = begin{bmatrix}t_1 & cdots & t_n end{bmatrix}$, where $t_j$'s are $ntimes 1$ column matrices. Since $A$ is Hermitian with $n$ distinct eigenvalues, and $t_j$'s are normalized, ${t_j}_1^n$ satisfies $t_j^* t_k = delta_{j,k}$, thus
        $$
        T^* T = [t_j^* t_k]_{(j,k)=(1,1)}^{(n,n)} = [delta_{j,k}] = I.
        $$







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        share|cite|improve this answer



        share|cite|improve this answer










        answered Dec 5 '18 at 3:45









        xbhxbh

        6,1251522




        6,1251522






























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