Linear Algebra - Proof on Linear Transformations and Independence

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Let $T: BbbR^n rightarrow BbbR^n$ be an invertible linear transformation. Prove that if $ vecv_1,vecv_2,...,vecv_n$ is a linearly independent set of $BbbR^n$ if and only if $T( vecv_1),T( vecv_2),...,T( vecv_k)$ is a linearly independent set of $BbbR^n$.




So I know that for a set of vectors to be linearly independent then they cannot be written as a linear combination of one another. So can I say something along the lines of $t_1 v_1 + t_2 v_2 + ... + t_k v_k = 0$ then taking the transformations the set I get is $T( t_1 vecv_1),T( t_2 vecv_2),...,T( t_k vecv_k)$ which given the definition of linear independence can be written as $ t_1 T( vecv_1) + t_2 T( vecv_2) +,..., + t_k T( vecv_k) = 0$. So then is that it?










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  • Yes. You have the right line of thinking. Be careful:you've only shown that a linear combination in the domain implies a linear combination in the range. You may want to remark why none of the images T(v$_i$) can be 0 in this situation. Otherwise, a non-trivial solution may map to a trivial solution if certain images are 0.
    – Joel Pereira
    4 hours ago














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Let $T: BbbR^n rightarrow BbbR^n$ be an invertible linear transformation. Prove that if $ vecv_1,vecv_2,...,vecv_n$ is a linearly independent set of $BbbR^n$ if and only if $T( vecv_1),T( vecv_2),...,T( vecv_k)$ is a linearly independent set of $BbbR^n$.




So I know that for a set of vectors to be linearly independent then they cannot be written as a linear combination of one another. So can I say something along the lines of $t_1 v_1 + t_2 v_2 + ... + t_k v_k = 0$ then taking the transformations the set I get is $T( t_1 vecv_1),T( t_2 vecv_2),...,T( t_k vecv_k)$ which given the definition of linear independence can be written as $ t_1 T( vecv_1) + t_2 T( vecv_2) +,..., + t_k T( vecv_k) = 0$. So then is that it?










share|cite|improve this question























  • Yes. You have the right line of thinking. Be careful:you've only shown that a linear combination in the domain implies a linear combination in the range. You may want to remark why none of the images T(v$_i$) can be 0 in this situation. Otherwise, a non-trivial solution may map to a trivial solution if certain images are 0.
    – Joel Pereira
    4 hours ago












up vote
1
down vote

favorite









up vote
1
down vote

favorite












Let $T: BbbR^n rightarrow BbbR^n$ be an invertible linear transformation. Prove that if $ vecv_1,vecv_2,...,vecv_n$ is a linearly independent set of $BbbR^n$ if and only if $T( vecv_1),T( vecv_2),...,T( vecv_k)$ is a linearly independent set of $BbbR^n$.




So I know that for a set of vectors to be linearly independent then they cannot be written as a linear combination of one another. So can I say something along the lines of $t_1 v_1 + t_2 v_2 + ... + t_k v_k = 0$ then taking the transformations the set I get is $T( t_1 vecv_1),T( t_2 vecv_2),...,T( t_k vecv_k)$ which given the definition of linear independence can be written as $ t_1 T( vecv_1) + t_2 T( vecv_2) +,..., + t_k T( vecv_k) = 0$. So then is that it?










share|cite|improve this question
















Let $T: BbbR^n rightarrow BbbR^n$ be an invertible linear transformation. Prove that if $ vecv_1,vecv_2,...,vecv_n$ is a linearly independent set of $BbbR^n$ if and only if $T( vecv_1),T( vecv_2),...,T( vecv_k)$ is a linearly independent set of $BbbR^n$.




So I know that for a set of vectors to be linearly independent then they cannot be written as a linear combination of one another. So can I say something along the lines of $t_1 v_1 + t_2 v_2 + ... + t_k v_k = 0$ then taking the transformations the set I get is $T( t_1 vecv_1),T( t_2 vecv_2),...,T( t_k vecv_k)$ which given the definition of linear independence can be written as $ t_1 T( vecv_1) + t_2 T( vecv_2) +,..., + t_k T( vecv_k) = 0$. So then is that it?







linear-algebra proof-verification linear-transformations






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edited 4 hours ago









Chinnapparaj R

3,818724




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FundementalJTheorem

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  • Yes. You have the right line of thinking. Be careful:you've only shown that a linear combination in the domain implies a linear combination in the range. You may want to remark why none of the images T(v$_i$) can be 0 in this situation. Otherwise, a non-trivial solution may map to a trivial solution if certain images are 0.
    – Joel Pereira
    4 hours ago
















  • Yes. You have the right line of thinking. Be careful:you've only shown that a linear combination in the domain implies a linear combination in the range. You may want to remark why none of the images T(v$_i$) can be 0 in this situation. Otherwise, a non-trivial solution may map to a trivial solution if certain images are 0.
    – Joel Pereira
    4 hours ago















Yes. You have the right line of thinking. Be careful:you've only shown that a linear combination in the domain implies a linear combination in the range. You may want to remark why none of the images T(v$_i$) can be 0 in this situation. Otherwise, a non-trivial solution may map to a trivial solution if certain images are 0.
– Joel Pereira
4 hours ago




Yes. You have the right line of thinking. Be careful:you've only shown that a linear combination in the domain implies a linear combination in the range. You may want to remark why none of the images T(v$_i$) can be 0 in this situation. Otherwise, a non-trivial solution may map to a trivial solution if certain images are 0.
– Joel Pereira
4 hours ago










1 Answer
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For $Longrightarrow$ : You are on the right way!



$t_1T(v_1)+t_2T(v_2)+cdots+t_nT(v_n)=0 $ implies $$T(t_1v_1+cdots+t_nv_n)=0=T(0)$$ and so by one-one of $T$, $$t_1v_1+cdots+t_nv_n=0$$



and by independence of $v_i$, $$t_1=t_2=cdots=t_n=0$$




For $Longleftarrow$ : Let $alpha_1v_1+alpha_2v_2+cdots+alpha_nv_n=0$ and apply $T$ on both sides and use independence of $T(v_i)$'s to get the result!






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    1 Answer
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    active

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    1 Answer
    1






    active

    oldest

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    active

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    active

    oldest

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    up vote
    3
    down vote













    For $Longrightarrow$ : You are on the right way!



    $t_1T(v_1)+t_2T(v_2)+cdots+t_nT(v_n)=0 $ implies $$T(t_1v_1+cdots+t_nv_n)=0=T(0)$$ and so by one-one of $T$, $$t_1v_1+cdots+t_nv_n=0$$



    and by independence of $v_i$, $$t_1=t_2=cdots=t_n=0$$




    For $Longleftarrow$ : Let $alpha_1v_1+alpha_2v_2+cdots+alpha_nv_n=0$ and apply $T$ on both sides and use independence of $T(v_i)$'s to get the result!






    share|cite|improve this answer


























      up vote
      3
      down vote













      For $Longrightarrow$ : You are on the right way!



      $t_1T(v_1)+t_2T(v_2)+cdots+t_nT(v_n)=0 $ implies $$T(t_1v_1+cdots+t_nv_n)=0=T(0)$$ and so by one-one of $T$, $$t_1v_1+cdots+t_nv_n=0$$



      and by independence of $v_i$, $$t_1=t_2=cdots=t_n=0$$




      For $Longleftarrow$ : Let $alpha_1v_1+alpha_2v_2+cdots+alpha_nv_n=0$ and apply $T$ on both sides and use independence of $T(v_i)$'s to get the result!






      share|cite|improve this answer
























        up vote
        3
        down vote










        up vote
        3
        down vote









        For $Longrightarrow$ : You are on the right way!



        $t_1T(v_1)+t_2T(v_2)+cdots+t_nT(v_n)=0 $ implies $$T(t_1v_1+cdots+t_nv_n)=0=T(0)$$ and so by one-one of $T$, $$t_1v_1+cdots+t_nv_n=0$$



        and by independence of $v_i$, $$t_1=t_2=cdots=t_n=0$$




        For $Longleftarrow$ : Let $alpha_1v_1+alpha_2v_2+cdots+alpha_nv_n=0$ and apply $T$ on both sides and use independence of $T(v_i)$'s to get the result!






        share|cite|improve this answer














        For $Longrightarrow$ : You are on the right way!



        $t_1T(v_1)+t_2T(v_2)+cdots+t_nT(v_n)=0 $ implies $$T(t_1v_1+cdots+t_nv_n)=0=T(0)$$ and so by one-one of $T$, $$t_1v_1+cdots+t_nv_n=0$$



        and by independence of $v_i$, $$t_1=t_2=cdots=t_n=0$$




        For $Longleftarrow$ : Let $alpha_1v_1+alpha_2v_2+cdots+alpha_nv_n=0$ and apply $T$ on both sides and use independence of $T(v_i)$'s to get the result!







        share|cite|improve this answer














        share|cite|improve this answer



        share|cite|improve this answer








        edited 4 hours ago

























        answered 4 hours ago









        Chinnapparaj R

        3,818724




        3,818724



























             

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