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I would like to clarify something in regards to finding a determinant of a matrix. For example say I have this problem where I have to evaluate the determinant:

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Is the determinant notation simply a reference to the notion that you are supposed to find the determinant?(as in an operation) So in other words, could I write this matrix with bracket notation if I wanted to? (or if there were no instructions, say)

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    @MarcvanLeeuwen: I seem to have missed the throwaway comment in *The TeX Book* (bottom of page 176); I always assumed `\pmatrix` had been added in LaTeX.2011-11-28

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Frequent notations for a matrix are

$\begin{pmatrix}a& b\\ c&d\end{pmatrix}$ and $\begin{bmatrix}a& b\\ c&d\end{bmatrix}$.

Frequent notations for determinants are

$\left|\begin{matrix}a& b\\ c&d\end{matrix}\right|$ and $\left\|\begin{matrix}a& b\\ c&d\end{matrix}\right\|$ and, of course, $\det\begin{pmatrix}a& b\\ c&d\end{pmatrix}$ and $\det\begin{bmatrix}a& b\\ c&d\end{bmatrix}$.

Brackets are sometimes used for determinants if the matrix is given by its row or column vectors, so if $v$ and $w$ are vectors with 2 coordinates then $[v,w]$ might be used for the determinant of the corresponding matrix.

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    Then we take "||" in latex instead of "\|".2011-11-26