To me it seems basic question or even obvious but as I am not mathematician I would rather like to check.(adsbygoogle = window.adsbygoogle || []).push({});

Is it true that these two matrices are both identity matrices: ##\begin{pmatrix}1&0\\0&1\end{pmatrix} ## and ##\begin{pmatrix}\frac{1}{\sqrt2}&-\frac{1}{\sqrt2}\\\frac{1}{\sqrt2}&\frac{1}{\sqrt2}\end{pmatrix}##? It's just that one of them would become diagonal with the right change of basis and the diagonal one would not be diagonal any more with that change of basis, right?

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# B Is identity matrix basis dependent?

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