$T:V \to V, \dim V$ is finite.
Let $V$ be a finite-dimensional vector space, and $\beta$ ordered basis of $V$.
Let $I_V: V \to V$ is defined as $I_V(x) = x \forall x \in V, $ i.e. $I_V =$ identity matrix. Let $Q = [I_V]$, then
- $Q$ is invertible
- $Q [ v ]_{ \beta' } = [ \beta ]$
The matrix $Q= [ I_V ]_{ \beta' }^{ \beta }$ is called the change of coordinate matrix from $\beta'$ -coordinate to $\beta$-coordinate.
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<span class="proof__expand"><a>[expand]</a></span>
$T: V \to V, \dim V $ is finite and $\beta$ and $\beta' $ is ordered basis of $V$.
$$[ T ]_{ \beta' } = \inv{ Q } [ T ]_{ \beta } Q$$
where $Q $ is the change of coordinate matrix from $\beta'$ to $\beta $.
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<span class="proof__expand"><a>[expand]</a></span>
Let $A \in M_{n \times n} (F) $, and let $\gamma $ be an ordered basis for $F^n $, then $[ L_A ]_{ \gamma } = \inv{ Q } A Q $, where $Q$ is the $n \times n $ matrix whose $j $th column is the $j$th vector of $\gamma $.
Let $A $ and $B $ be two $n \times n $ matrices, then $A $ and $B $ are similar if $\exists $ and invertible matrix $Q$ s.t. $B = \inv{ Q } AQ $.
Two matrices $T $ with respect to different ordered basis are similar to each other.
$A$ is invertible matrix if and only if it is a change of coordinate matrix.
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<span class="proof__expand"><a>[expand]</a></span>