Find a change-of-coordinates matrix $P$ and use it to show that $A$ is similar to $begin{bmatrix} a & -b...












0















Let $A = begin{bmatrix}
1 & 5 \
-1 & 3
end{bmatrix}$
act on $mathbb{C}^2$. An eigenvector of $A$ is $begin{bmatrix}
1-2i \
1
end{bmatrix}$
, corresponding to the eigenvalue $2+2i$. Find a change-of-coordinates matrix $P$ and use it to show that $A$ is similar to a matrix of the form $begin{bmatrix}
a & -b \
b & a
end{bmatrix}$
.




I know that Eigenvectors for $begin{bmatrix}
a & -b \
b & a
end{bmatrix}$
. are $begin{bmatrix}1\-iend{bmatrix}$ and $begin{bmatrix}1\iend{bmatrix}$. I believe I need to make a augmented matrix and row reduce yet still unsure how to approach it.










share|cite|improve this question
























  • A real polynomial has conjugate roots.
    – GNUSupporter 8964民主女神 地下教會
    Nov 29 at 9:40






  • 1




    They will be similar if they have common eigenvalues. From this you obtain $a,b.$ Then one can go through the diagonalization on each of matrices. There can exist a more elegant method...this one will works as well.
    – user376343
    Nov 29 at 10:01










  • Play around with the real and imaginary parts of the eigenvectors.
    – amd
    Nov 29 at 20:00
















0















Let $A = begin{bmatrix}
1 & 5 \
-1 & 3
end{bmatrix}$
act on $mathbb{C}^2$. An eigenvector of $A$ is $begin{bmatrix}
1-2i \
1
end{bmatrix}$
, corresponding to the eigenvalue $2+2i$. Find a change-of-coordinates matrix $P$ and use it to show that $A$ is similar to a matrix of the form $begin{bmatrix}
a & -b \
b & a
end{bmatrix}$
.




I know that Eigenvectors for $begin{bmatrix}
a & -b \
b & a
end{bmatrix}$
. are $begin{bmatrix}1\-iend{bmatrix}$ and $begin{bmatrix}1\iend{bmatrix}$. I believe I need to make a augmented matrix and row reduce yet still unsure how to approach it.










share|cite|improve this question
























  • A real polynomial has conjugate roots.
    – GNUSupporter 8964民主女神 地下教會
    Nov 29 at 9:40






  • 1




    They will be similar if they have common eigenvalues. From this you obtain $a,b.$ Then one can go through the diagonalization on each of matrices. There can exist a more elegant method...this one will works as well.
    – user376343
    Nov 29 at 10:01










  • Play around with the real and imaginary parts of the eigenvectors.
    – amd
    Nov 29 at 20:00














0












0








0








Let $A = begin{bmatrix}
1 & 5 \
-1 & 3
end{bmatrix}$
act on $mathbb{C}^2$. An eigenvector of $A$ is $begin{bmatrix}
1-2i \
1
end{bmatrix}$
, corresponding to the eigenvalue $2+2i$. Find a change-of-coordinates matrix $P$ and use it to show that $A$ is similar to a matrix of the form $begin{bmatrix}
a & -b \
b & a
end{bmatrix}$
.




I know that Eigenvectors for $begin{bmatrix}
a & -b \
b & a
end{bmatrix}$
. are $begin{bmatrix}1\-iend{bmatrix}$ and $begin{bmatrix}1\iend{bmatrix}$. I believe I need to make a augmented matrix and row reduce yet still unsure how to approach it.










share|cite|improve this question
















Let $A = begin{bmatrix}
1 & 5 \
-1 & 3
end{bmatrix}$
act on $mathbb{C}^2$. An eigenvector of $A$ is $begin{bmatrix}
1-2i \
1
end{bmatrix}$
, corresponding to the eigenvalue $2+2i$. Find a change-of-coordinates matrix $P$ and use it to show that $A$ is similar to a matrix of the form $begin{bmatrix}
a & -b \
b & a
end{bmatrix}$
.




I know that Eigenvectors for $begin{bmatrix}
a & -b \
b & a
end{bmatrix}$
. are $begin{bmatrix}1\-iend{bmatrix}$ and $begin{bmatrix}1\iend{bmatrix}$. I believe I need to make a augmented matrix and row reduce yet still unsure how to approach it.







linear-algebra change-of-basis






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Nov 29 at 9:38









GNUSupporter 8964民主女神 地下教會

12.8k72445




12.8k72445










asked Nov 29 at 8:29









HighSchool15

1,065517




1,065517












  • A real polynomial has conjugate roots.
    – GNUSupporter 8964民主女神 地下教會
    Nov 29 at 9:40






  • 1




    They will be similar if they have common eigenvalues. From this you obtain $a,b.$ Then one can go through the diagonalization on each of matrices. There can exist a more elegant method...this one will works as well.
    – user376343
    Nov 29 at 10:01










  • Play around with the real and imaginary parts of the eigenvectors.
    – amd
    Nov 29 at 20:00


















  • A real polynomial has conjugate roots.
    – GNUSupporter 8964民主女神 地下教會
    Nov 29 at 9:40






  • 1




    They will be similar if they have common eigenvalues. From this you obtain $a,b.$ Then one can go through the diagonalization on each of matrices. There can exist a more elegant method...this one will works as well.
    – user376343
    Nov 29 at 10:01










  • Play around with the real and imaginary parts of the eigenvectors.
    – amd
    Nov 29 at 20:00
















A real polynomial has conjugate roots.
– GNUSupporter 8964民主女神 地下教會
Nov 29 at 9:40




A real polynomial has conjugate roots.
– GNUSupporter 8964民主女神 地下教會
Nov 29 at 9:40




1




1




They will be similar if they have common eigenvalues. From this you obtain $a,b.$ Then one can go through the diagonalization on each of matrices. There can exist a more elegant method...this one will works as well.
– user376343
Nov 29 at 10:01




They will be similar if they have common eigenvalues. From this you obtain $a,b.$ Then one can go through the diagonalization on each of matrices. There can exist a more elegant method...this one will works as well.
– user376343
Nov 29 at 10:01












Play around with the real and imaginary parts of the eigenvectors.
– amd
Nov 29 at 20:00




Play around with the real and imaginary parts of the eigenvectors.
– amd
Nov 29 at 20:00















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