> 
> Let $T:P\_2 \to P\_1$ be defined by $T(p(x))=p'(x) + p''(x)$ and let $B = \{1,x,x^2\} \text{ and } B'=\{1,x\}$.
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> Find $[T]\_{B\prime \to B}$
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> 
> 

I do not understand the notation used when saying $[T]\_{\textbf{B' $\to$ B}}$.

Can anybody please explain to me how to do this? Or show me another example? I simply do not have any references to understand the notation and hence cannot go about finding the answer.