Finding the matrix $A$ of $T$ with respect to the basis

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Let $T:mathbbR^3rightarrowmathbbR^3$ be given by
$$Tleft(beginbmatrix x \ y \ z endbmatrixright)=beginbmatrix x-y \ y-z \ z-x endbmatrix$$
Find the matrix $A$ of $T$ with respect to the basis
$$beginbmatrix -1 \ 0 \ 1 endbmatrixbeginbmatrix 1 \ 1 \ 1 endbmatrixbeginbmatrix 0 \ 1 \ 0 endbmatrix$$




My try:



I found $Tleft(beginbmatrix x \ y \ z endbmatrixright)=xbeginbmatrix 1 \ 0 \ -1 endbmatrix+ybeginbmatrix -1 \ 1 \ 0 endbmatrix+zbeginbmatrix 0 \ -1 \ 1 endbmatrix$



Now,



$$beginbmatrix -1 & 1 & 0 \ 0 & 1 & 1 \ 1 & 1 & 0 endbmatrixbeginbmatrix -1 \ 0 \ 1 endbmatrix=beginbmatrix 1 \ 1 \ -1 endbmatrix$$



In the same way I found the other matrices as
$$beginbmatrix 0 \ 2 \ 2 endbmatrix,beginbmatrix 1 \ 1 \ 1 endbmatrix$$
Now,
$$beginbmatrix 1 \ 1 \ -1 endbmatrix=abeginbmatrix -1 \ 0 \ 1 endbmatrix+bbeginbmatrix 1 \ 1 \ 1 endbmatrix+cbeginbmatrix 0 \ 1 \ 0 endbmatrix$$
So, if I find $a,b,c$ then that will become the first row of my required matrix right? Can anyone tell whether this method is correct or not?







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  • Recall that the i-th column of the matrix should be the i-th basis vector passed through the transformation and than shown in the given basis
    – GuySa
    Jul 18 at 16:37














up vote
1
down vote

favorite













Let $T:mathbbR^3rightarrowmathbbR^3$ be given by
$$Tleft(beginbmatrix x \ y \ z endbmatrixright)=beginbmatrix x-y \ y-z \ z-x endbmatrix$$
Find the matrix $A$ of $T$ with respect to the basis
$$beginbmatrix -1 \ 0 \ 1 endbmatrixbeginbmatrix 1 \ 1 \ 1 endbmatrixbeginbmatrix 0 \ 1 \ 0 endbmatrix$$




My try:



I found $Tleft(beginbmatrix x \ y \ z endbmatrixright)=xbeginbmatrix 1 \ 0 \ -1 endbmatrix+ybeginbmatrix -1 \ 1 \ 0 endbmatrix+zbeginbmatrix 0 \ -1 \ 1 endbmatrix$



Now,



$$beginbmatrix -1 & 1 & 0 \ 0 & 1 & 1 \ 1 & 1 & 0 endbmatrixbeginbmatrix -1 \ 0 \ 1 endbmatrix=beginbmatrix 1 \ 1 \ -1 endbmatrix$$



In the same way I found the other matrices as
$$beginbmatrix 0 \ 2 \ 2 endbmatrix,beginbmatrix 1 \ 1 \ 1 endbmatrix$$
Now,
$$beginbmatrix 1 \ 1 \ -1 endbmatrix=abeginbmatrix -1 \ 0 \ 1 endbmatrix+bbeginbmatrix 1 \ 1 \ 1 endbmatrix+cbeginbmatrix 0 \ 1 \ 0 endbmatrix$$
So, if I find $a,b,c$ then that will become the first row of my required matrix right? Can anyone tell whether this method is correct or not?







share|cite|improve this question



















  • Recall that the i-th column of the matrix should be the i-th basis vector passed through the transformation and than shown in the given basis
    – GuySa
    Jul 18 at 16:37












up vote
1
down vote

favorite









up vote
1
down vote

favorite












Let $T:mathbbR^3rightarrowmathbbR^3$ be given by
$$Tleft(beginbmatrix x \ y \ z endbmatrixright)=beginbmatrix x-y \ y-z \ z-x endbmatrix$$
Find the matrix $A$ of $T$ with respect to the basis
$$beginbmatrix -1 \ 0 \ 1 endbmatrixbeginbmatrix 1 \ 1 \ 1 endbmatrixbeginbmatrix 0 \ 1 \ 0 endbmatrix$$




My try:



I found $Tleft(beginbmatrix x \ y \ z endbmatrixright)=xbeginbmatrix 1 \ 0 \ -1 endbmatrix+ybeginbmatrix -1 \ 1 \ 0 endbmatrix+zbeginbmatrix 0 \ -1 \ 1 endbmatrix$



Now,



$$beginbmatrix -1 & 1 & 0 \ 0 & 1 & 1 \ 1 & 1 & 0 endbmatrixbeginbmatrix -1 \ 0 \ 1 endbmatrix=beginbmatrix 1 \ 1 \ -1 endbmatrix$$



In the same way I found the other matrices as
$$beginbmatrix 0 \ 2 \ 2 endbmatrix,beginbmatrix 1 \ 1 \ 1 endbmatrix$$
Now,
$$beginbmatrix 1 \ 1 \ -1 endbmatrix=abeginbmatrix -1 \ 0 \ 1 endbmatrix+bbeginbmatrix 1 \ 1 \ 1 endbmatrix+cbeginbmatrix 0 \ 1 \ 0 endbmatrix$$
So, if I find $a,b,c$ then that will become the first row of my required matrix right? Can anyone tell whether this method is correct or not?







share|cite|improve this question












Let $T:mathbbR^3rightarrowmathbbR^3$ be given by
$$Tleft(beginbmatrix x \ y \ z endbmatrixright)=beginbmatrix x-y \ y-z \ z-x endbmatrix$$
Find the matrix $A$ of $T$ with respect to the basis
$$beginbmatrix -1 \ 0 \ 1 endbmatrixbeginbmatrix 1 \ 1 \ 1 endbmatrixbeginbmatrix 0 \ 1 \ 0 endbmatrix$$




My try:



I found $Tleft(beginbmatrix x \ y \ z endbmatrixright)=xbeginbmatrix 1 \ 0 \ -1 endbmatrix+ybeginbmatrix -1 \ 1 \ 0 endbmatrix+zbeginbmatrix 0 \ -1 \ 1 endbmatrix$



Now,



$$beginbmatrix -1 & 1 & 0 \ 0 & 1 & 1 \ 1 & 1 & 0 endbmatrixbeginbmatrix -1 \ 0 \ 1 endbmatrix=beginbmatrix 1 \ 1 \ -1 endbmatrix$$



In the same way I found the other matrices as
$$beginbmatrix 0 \ 2 \ 2 endbmatrix,beginbmatrix 1 \ 1 \ 1 endbmatrix$$
Now,
$$beginbmatrix 1 \ 1 \ -1 endbmatrix=abeginbmatrix -1 \ 0 \ 1 endbmatrix+bbeginbmatrix 1 \ 1 \ 1 endbmatrix+cbeginbmatrix 0 \ 1 \ 0 endbmatrix$$
So, if I find $a,b,c$ then that will become the first row of my required matrix right? Can anyone tell whether this method is correct or not?









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asked Jul 18 at 4:09









philip

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  • Recall that the i-th column of the matrix should be the i-th basis vector passed through the transformation and than shown in the given basis
    – GuySa
    Jul 18 at 16:37
















  • Recall that the i-th column of the matrix should be the i-th basis vector passed through the transformation and than shown in the given basis
    – GuySa
    Jul 18 at 16:37















Recall that the i-th column of the matrix should be the i-th basis vector passed through the transformation and than shown in the given basis
– GuySa
Jul 18 at 16:37




Recall that the i-th column of the matrix should be the i-th basis vector passed through the transformation and than shown in the given basis
– GuySa
Jul 18 at 16:37










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You haven't actually applied $T$ to any of the basis vectors (the matrix you have there is the matrix with the basis vectors as columns, and as such it has little to do with $T$).



If you apply $T$ to the first basis vector, you get $[-1,-1,2]^T$. Now that is the vector you should express as a linear combination of the basis vectors, and the coefficients make up the first column of $A$.






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    1 Answer
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    active

    oldest

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    1 Answer
    1






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    oldest

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    active

    oldest

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    up vote
    2
    down vote



    accepted










    You haven't actually applied $T$ to any of the basis vectors (the matrix you have there is the matrix with the basis vectors as columns, and as such it has little to do with $T$).



    If you apply $T$ to the first basis vector, you get $[-1,-1,2]^T$. Now that is the vector you should express as a linear combination of the basis vectors, and the coefficients make up the first column of $A$.






    share|cite|improve this answer

























      up vote
      2
      down vote



      accepted










      You haven't actually applied $T$ to any of the basis vectors (the matrix you have there is the matrix with the basis vectors as columns, and as such it has little to do with $T$).



      If you apply $T$ to the first basis vector, you get $[-1,-1,2]^T$. Now that is the vector you should express as a linear combination of the basis vectors, and the coefficients make up the first column of $A$.






      share|cite|improve this answer























        up vote
        2
        down vote



        accepted







        up vote
        2
        down vote



        accepted






        You haven't actually applied $T$ to any of the basis vectors (the matrix you have there is the matrix with the basis vectors as columns, and as such it has little to do with $T$).



        If you apply $T$ to the first basis vector, you get $[-1,-1,2]^T$. Now that is the vector you should express as a linear combination of the basis vectors, and the coefficients make up the first column of $A$.






        share|cite|improve this answer













        You haven't actually applied $T$ to any of the basis vectors (the matrix you have there is the matrix with the basis vectors as columns, and as such it has little to do with $T$).



        If you apply $T$ to the first basis vector, you get $[-1,-1,2]^T$. Now that is the vector you should express as a linear combination of the basis vectors, and the coefficients make up the first column of $A$.







        share|cite|improve this answer













        share|cite|improve this answer



        share|cite|improve this answer











        answered Jul 18 at 5:44









        Arthur

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