Is it true to say that if [itex]X^T X[/itex] is non-singular, then the column vectors of X must be linearly independent? I know how to prove that if the columns of X are linearly independent, then [itex]X^T X[/itex] is non-singular. Just not sure about the other way around. Thanks!(adsbygoogle = window.adsbygoogle || []).push({});

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# Non-singularity of A^T*A

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