Testing stretchy MathML symbols

Testing stretchy symbols -- view the source...

{(... {({(a_{0} + a_{1})}^{n_{1}} + a_{2})}^{n_{2}} + ... + a^{p})}^{n^{p}}

A = [\begin{matrix} x & y \\ z & w \end{matrix}];

x + (\frac{a}{b});

in binomial formulas

(\binom{n}{p}) = (\binom{n - 1}{p}) + (\binom{n - 1}{p - 1}); {(a + b)}^{n} = a^{n} + (\binom{n}{1}) a^{n - 1} b + ... + (\binom{n}{p}) a^{n - p} b^{p} + ... + b^{n}

and elsewhere,

{a_{0} + \frac{1}{a_{1} + \frac{1}{a_{2} + \frac{1}{a_{3}}}}; \overset{⏞}{aa + bb}; \underset{\to}{b + c + d}; {a + b + c + d}_{\to}^{\leftarrow}; (\frac{1 + \sqrt{5}}{2}); x = \frac{- b \pm \sqrt{b^{2} - 4 a c}}{2 a} ({↑ \int \frac{\frac{n {n + 1)}{2}}{y} ↓}) x \overset{maps to}{\to} y