Type then will see:


MathJax Text 1: \begin{pmatrix}n \\ k \end{pmatrix}


MathJax Text 2:



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MathJax basic tutorial and quick reference
UTF-8 Mathematical Operators

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Sample 1

    \begin{pmatrix}n \\ k \end{pmatrix} = \begin{cases} \begin{pmatrix}n - 1 \\ k - 1 \end{pmatrix} + \begin{pmatrix}n - 1 \\ k \end{pmatrix} &\mbox { if } 0 < k < n \\ 1 &\mbox { if } \: k = 0 \: or \: k = n \end{cases}

$\begin{pmatrix}n \\ k \end{pmatrix} = \begin{cases} \begin{pmatrix}n - 1 \\ k - 1 \end{pmatrix} + \begin{pmatrix}n - 1 \\ k \end{pmatrix} &\mbox { if } 0 < k < n \\ 1 &\mbox { if } \: k = 0 \: or \: k = n \end{cases}$

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Sample 2

x = {-b \pm \sqrt{b^2-4ac} \over 2a}

$x = {-b \pm \sqrt{b^2-4ac} \over 2a}$

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Sample 3

\begin{equation}f(x) = \frac{1}{\sqrt{2\pi}} e^{-\frac12 x^2}\end{equation}

$\begin{equation}f(x) = \frac{1}{\sqrt{2\pi}} e^{-\frac12 x^2}\end{equation}$

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