Sandbox

Math: $u=\int _{0}^{w}f(a,u)dt$

Ugly stuff: ${\textstyle a\implies b}$

Displayed equation:

${\begin{aligned}x&=1\\y&=2\end{aligned}}$

AMS Math: <amsmath> u = \int_0^h f(a,u) dt </amsmath>

Interwiki link: FBS wiki